BARR/3270 manual

5. Software Installation

Menu-driven

This chapter presents software installation of the BARR/3270 program step-by-step from installation to startup. The entire software installation process is menu-driven. After you have used BARR/3270 once, you will find your way through the program easily.


5.1 Distribution Diskette(s)

Disk size

BARR/3270 software is available on 3 1 §2" or 5 1 §4" diskette(s) and operates on an IBM PC, XT, AT, PS/2 series, or compatible computer.

Disk drive

You can install BARR/3270 on a one-drive, two-drive, or hard drive computer. The instructions will vary slightly depending on the type of PC you specify when you install the program. The BARR/3270 Installation Program documents itself on the screen. If installing on a diskette-based PC, you will need a blank diskette which will become the production diskette.

Load disk

Start the PC using DOS 3.0 or a later version. If you are using a monochrome monitor on a color adapter (CGA, EGA, VGA), from the DOS prompt enter:

Put the distribution disk in drive A.

At the DOS prompt:

Type A:INSTALL

Type 1, 2, or 3, depending on your type PC. This example shows a hard drive installation.

Type the drive letter.

Type directory name in which to install BARR/3270.

Press ENTER. Files on the BARR/3270 distribution diskette will be copied to the directory you specified on the previous screen.

Press ENTER. For step-by step instructions, proceed to the Installation Description.

5.2 Installation Description

Logon profile

The Installation Description informs BARR/3270 about your PC and 3270 workstation profile. Once completed, the BARR/3270 program automatically performs Logon each time using the information you provided at installation. If you decide to change this information, you can reenter the Installation Description at any time by exiting and then reentering BARR/3270. To access the Installation program, type

BARR3270 I

at the DOS prompt.

Press any key.

If the words Any key in the bottom right corner of the screen are unreadable, you need to exit BARR/3270 and enter the MODE BW80 from DOS before proceeding. See the beginning of this section for instructions.

Press any key.

Describe your PC to BARR/3270 from the Installation Description screen.

Select 3270 Description.

5.3 3270 Description

On the 3270 Description screen you define the number of 3270 sessions and the terminal.

Number of 3270 sessions?

Select 0 to 4 3270 sessions.

Keyboard Type?

Select the type of keyboard that is attached to the PC:

IBM AT IBMís 83/84 key keyboard

IBM Enhanced 101/102 IBMís 101/102 key keyboard

IBM PC/XT Like the AT keyboard, but some keys are located differently

IBM 3270PC IBMís 3270 PC Keyboard

Default The software determines whether the keyboard type is IBM AT or IBM Enhanced 101/102

Key Tronic KB3270/PC Same as IBM 3270PC. Set the keyboard switches to IBM AT mode. See your Key Tronic manual for switch settings.

To use the Key Tronic keyboard in IRMA mode, select the IRMA keyboard type in the Barr software and set the keyboard switches to IRMA mode. See your Key Tronic manual for switch settings.

IRMA 3270 Keyboard Same as IBM 3270PC. See also Key Tronic KB3270/PC above.

IBM Foreign 102 Key Refers to IBM Enhanced 101/102 Keyboard with language-specific key tops. This option displays the Keyboard Training Utility described later.

Edit Keyboard Map?

No Default. Use the default keyboard map that was supplied.

Yes Edit the keyboard map. This option displays the Keyboard Map described later.

Use Intense Colors?

Yes Default. Use intense 3270 field colors to enhance readability on some terminals.

No Use regular 3270 field colors.

Enable HLLAPI Interface?

Yes Default. Enable the EHLLAPI Interface. Required for file transfer.

No Disable the EHLLAPI Interface.

HLLAPI Storage Manager (KBytes)?

In addition to the 8K of memory provided initially, allocate more memory space for applications requiring Storage Manager support. Up to 32K of additional memory can be specified.

Enable File Transfer?

Yes Default. Install the IND$FILE file transfer protocol.

No Do not install the file transfer protocol.

Data Packet Size?

Inbound data packet size used during file transfer. In 3270 file transfer, a packet is the amount of data sent to the host before a response is required. You can specify a data packet size from 1000 to 8000 bytes, depending on your host. The IBM default packet size is 4000 bytes.

Host File Transfer Command?

Name given to the host file transfer program. The default is IND$FILE; CICS uses the name FT01. The name can have up to 8 characters.

Press ENTER. A session information screen displays if a non-zero number of 3270 sessions is specified.

Session Information

Specify the information related to a particular 3270 session.

Session

The number of the 3270 session.

Name

An eight-character name you assign to the session. Since you can use the first character of the name to hot key to the session, assign each session a name with a unique first character.

Models

Specify the display terminal model type or printer you want to emulate. (Models 3, 4, and 5 use more memory.)

2 Emulate a 3278 or 3279 Model 2 (24x80)

2,3 Emulate a 3278 or 3279 Model 3 (32x80)

2,3,4 Emulate a 3278 or 3279 Model 4 (43x80)

2,3,4,5 Emulate a 3278 or 3279 Model 5 (27x132)

Printer Emulate a 3287 LU1 or LU3 type printer. Actual printer type is determined when the session begins.

The 3270 printer session acts like a host-connected 3287 printer. The LU type of the printer (LU1 or LU3) is determined when the 3270 session is bound to the host application. Sample LOGMODEs for LU1 and LU3 type printers are shown in Appendix D.

The LU1 (SCS) printer data stream is the same as the SCS RJE printer data stream, although SCS 3270 does not support data compaction or compression. The LU3 (DSC) printer data stream is similar to a display terminalís data stream but also contains print control orders. After the data stream is processed (as if it were for a display terminal), the contents of the 3270 buffer are printed to the output device.

Each 3270 printer session appears as a Source in Assign Devices. Source names for 3270 printers are prefixed with the string PR_. The first six non-blank characters of the session name are used as the suffix. 3270 printer Sources can be assigned to the allowed Destinations (printer, disk file, or screen).

Character-Coded Logon

A string of 40 characters that are automatically sent to the host during logon. The format used depends on what is acceptable to your host. This feature allows you to connect automatically to a particular host application during start-up. To logon manually from the 3270 screen, leave the logon string blank.

Edit fields. Press ENTER.

Keyboard Training Utility for IBM Foreign 102 Keyboard Type

If you choose IBM Foreign 102 as your keyboard type and select Yes for the Edit Keyboard Map? option, you go to the Keyboard Training Utility. This utility, which assures complete support for all present and future foreign keyboards, maps a key scan code to its corresponding printable ASCII character shown on the key top. This correspondence is used during Edit Keyboard Map to show key definitions. Below is the screen you see when you invoke this utility.

Before using the Keyboard Training Utility, you should load the appropriate code page and run the DOS KEYB program with parameters related to the desired language. Refer to your DOS manual for more information on how to do this.

Press each key labeled with a printable graphics character (for example A-Z, 0-9). As each key is entered, its legend is shown on the bottom part of the screen. Characters represented by two-key, or "dead key", combinations (for example ť, Ł) are ignored for some keyboards. Do not enter the two-key combinations.

Once you have entered all the printable graphics characters, press ESC to go to the Edit Keyboard Map utility.

When using a foreign keyboard, you need to choose the correct translation table for your language. This is documented in Section 6.1 under the Choose Language for Translation Tables option.

Edit Keyboard Map

Use this feature to map PC keys to 3270 keys. You can define a single PC keystroke or a two-key combination including a shift status key (such as the Shift, Alt, or Ctrl) to perform a 3270 key function.

Edit Keyboard Map?

No Do not display Edit Keyboard Map.

Yes Display the Edit Keyboard Map screen. For example, if you have an IBM Enhanced 101/102 key keyboard, you will see the default keyboard map shown below:

Select Show Map with the arrow keys to view current mappings of all 3270 keys. (This option is available during installation only.) Press ENTER to return.

To view mappings of the 3270 keys one at a time, select a 3270 key with the cursor. The 3270 key and its current PC key are shown at the bottom of the screen. For example, note that the 3270 ENTER key is mapped to the CTRL key on the right hand side of the PC keyboard.

To edit the map for a particular 3270 key, move the cursor to the 3270 key. Note whether or not the 3270 key has a PC key defined. Press ENTER. For the PF1 (assigned to F1), you see this screen:

Press the Space bar to undefine the key mappings for the 3270 key shown at the bottom of the Edit Keyboard Map screen. You will be returned to the Edit Keyboard Map Screen.

To assign a new PC key or two-key combination to the 3270 key, select the 3270 key again. When the Enter keys for: message appears,

press the desired PC key(s) on your keyboard.

If the PC key or key combination is already assigned to another 3270 key, an error message showing the 3270 key(s) in use appears.

Wait a few seconds and you will be returned automatically to the Edit Keyboard Map screen.

Select the 3270 key again and at the Enter keys for: field, press a new PC key combination.

The screen displays:

At the bottom of the screen, the 3270 key and the key definition entered for it are shown.

Press ENTER to replace all the previous key definitions for the 3270 key with the new key definition.

OR

Press the INS key on the numeric keypad to add the new key definition to the existing key definitions for the 3270 key. (Many different PC key combinations can be mapped to a single 3270 key.)

OR

Press ESC to ignore any change to the key definition and return to the Edit Keyboard Map screen.

Press ESC to return to the Installation Description.

5.3.0 Communication Link

The Communication Link describes the communications protocol and the physical attachment between the host system and the remote PC. VTAM is the mainframe program for the SNA communication protocol, and NCP is the program that resides in the mainframe communication controllers.

The PC on which BARR/3270 is installed is either connected to the mainframe with a modem, a Token Ring Network, or via the BARR/GATE SNA Gateway.

Modem Connections

The modem connection uses Synchronous Data Link Control (SDLC) to define how frames of data are sent and received.

Dial-up connections use the public phone system to send data at speeds from 1,200 to 9,600 bps. Dedicated point-to-point lines operate at speeds from 4,800 to 384,000 bps. Dedicated lines are either leased from a phone company or installed by the end user in a single building or campus.

Token Ring Connections

The Token Ring Network is a 4- or 16-megabit communications architecture that supports Local Area Networks (LANs) connecting PCs, minicomputers, mainframes, and other peripherals. The Token Ring Network is used by the LAN file server and by applications such as BARR/3270. The PC connects to the LAN by a Token Ring adapter and BARR/3270 software. The 3725 and 3745 communications controllers connect to the Token Ring Network by a Token Ring Interface Coupler (TIC). The 3174 Establishment Controllers use Token Ring adapters to connect to the Token Ring Network.

Gateway Connections

The BARR/GATE SNA gateway connects the mainframe SNA network to a LAN. BARR/GATE enables any PC on the LAN to use BARR/3270 without additional hardware. The LAN software interfaces NETBIOS, Novell IPX, and Token Ring are supported.

The following screen gives the Communication Link selections.

Select the Communication Link.

5.3.1 SDLC Dial Line (Switched)

SDLC dial lines have host modems that automatically answer phone calls made by remote users. The modems use the public phone system at speeds between 1,200 and 9,600 bps.

The SDLC Dial Line screen lists all the parameters needed by the BARR/3270 program and by VTAM and NCP on the mainframe. These parameters, which are entered into the host VTAM and NCP libraries, should be provided by the host communications programmer. After the Communication Link has been completed, BARR/3270 produces the statements that are entered into the VTAM and NCP parameter libraries.

NCP Parameters

The NCP parameters are specified by the LINE macro.

LINE Macro

NRZI=YES|NO

Non Return to Zero Inverted (NRZI) is a method of coding binary data with RS232 interface. Historically, there was reason to use it; at present its use relies on the convention of the host.

YES Use Non Return to Zero Inverted coding.

NO Do not use NRZI coding.

VTAM Parameters

The BARR/3270 workstation corresponds to a Physical Unit (PU) in VTAM. The physical unit consists of 2 to 20 Logical Units (LU). The VTAM parameters are specified by the PU Macro and LU Macro.

PU Macro

IDBLK=bbb
IDNUM=nnnnn

Parameters used on a dial-up line to identify the remoteís physical unit definition. The mainframe sends an Xid as the first message to a dial-up remote. The remote responds with an Xid that contains the IDBLK and IDNUM parameters.

VTAM searches for the physical unit identified by IDNUM and IDBLK. This physical unit is then used for the remainder of the communications session.

DATMODE=HALF|FULL

HALF In half duplex, the communications line is always either in a send or receive mode. Less than half the capacity of the line is available for use.

FULL Data is sent and received at the same time, resulting in twice the throughput. The V.32 modem standard supports full duplex on dial-up lines. Some modems do not support full-duplex communication.

MAXDATA=265|521|1033

The maximum amount of data that can be sent on the physical unit in one frame. This count includes 9 bytes of header information plus the data length.

NCP Definition for Dial Line

After pressing ENTER, the following screen will appear.

Press any key.

Selected NCP parameters are described below for reference. The parameters are divided into three groups: parameters that are especially important to BARR/3270, parameters that use system defaults, and other options that users commonly reset.

GROUP Macro

The GROUP macro instruction gives common settings for all parameters for line macros within the group.

Parameters BARR/3270 needs:

group

The name of a GROUP macro instruction is not used by VTAM or by BARR/3270.

DIAL=YES

This is a dial-up line.

LNCTL=SDLC

The line control is SDLC.

LINE Macro

The form of the instruction is:

Parameters BARR/3270 needs:

linename

The VTAM name of the communications line.

ADDRESS=aaa

Specifies the line interface address, aaa, if DATMODE=HALF is specified.

ADDRESS=(aaa,FULL),DUPLEX=FULL

Specifies the line interface address, aaa, if DATMODE=FULL is specified.

NRZI=YES|NO

Non Return to Zero Inverted (NRZI) is a method of coding binary data with RS232 interface. Historically, there was reason to use it; at present its use relies on the convention of the host.

YES Use Non Return to Zero Inverted coding.

NO Do not use NRZI coding.

RETRIES=(8,2,20)

Specifies the number of attempts to recover from communications errors. The general form is:

RETRIES=(m,t,n)

m Maximum retransmissions of frame while waiting for normal response

t Time in seconds paused after m retransmissions failed

n Number of times the above error recovery sequence is repeated

SPEED=nnnnnn

Must be specified. Since the modem provides the bits-per-second clock, this parameter has no effect on the functioning of BARR/3270. However, the IBM Network Performance Monitor uses this value to calculate statistics.

TRANSFR=16

Specifies the number of NCP buffers corresponding to the maximum amount of data (the data transfer limit) that the NCP is to receive from the line during a single data transfer operation.

BARR/3270 uses these system default values:

CHECK=NODCD

Specifies that the Data Carrier Detect line from the modem is not to be monitored.

CLOCKNG=EXT

External clocking indicates that the modemís clock will control the transmission rate.

PU Macro

The PU macro names and describes a physical unit. This PU macro is replaced at Logon with the PU macro that is stored in VTAM.

Parameters BARR/3270 needs:

puname

The physical unitís name conforms to your installationís naming convention. The VTAM operator uses the name to vary the unit as active or inactive and to query the unitís status.

MAXLU=n

The only important parameter of this PU is the maximum number of LUs that will ever be used with this line.

Physical Unit Definition of Dial Device

After pressing any key, the following screen will appear.

Press any key.

Selected parameters are described below for reference. The parameters are divided into three groups: parameters that are especially important to BARR/3270, parameters that use system defaults, and other options that users commonly reset.

PU Macro

The PU macro names and describes a physical unit.

Parameters BARR/3270 needs:

puname

The physical unitís name conforms to your installationís naming convention. The VTAM operator uses the name to vary the unit as active or inactive and to query the unitís status.

ADDR=C1

Is the 8-bit address used by SDLC. This address, the first byte of every frame, separates messages sent to different physical units on the same line.

DATMODE=HALF|FULL

HALF In half duplex, the communications line is always either in a send or receive mode. Less than half the capacity of the line is available for use.

FULL Data is sent and received at the same time, resulting in twice the throughput. The V.32 modem standard supports full duplex on dial-up lines. Some modems do not support full-duplex communication.

IDBLK=bbb
IDNUM=nnnnn

Parameters used on a dial-up line to identify the remoteís physical unit definition. The mainframe sends an Xid as the first message to a dial-up remote. The remote responds with an Xid that contains the IDBLK and IDNUM parameters.

VTAM searches for the physical unit identified by IDBLK and IDNUM. This physical unit is then used for the remainder of the communications session.

MAXDATA=265|521|1033

The maximum amount of data that can be sent on the physical unit in one frame. This count includes 9 bytes for header information plus the data length.

MAXOUT=7

Specifies that up to seven frames of information will be sent before pausing for a response. The maximum MAXOUT value of 7 results in highest throughput.

PACING=7

Determines how much data is sent to BARR/3270 before a pacing response is needed to send more data. Pacing is a flow control mechanism so that the mainframe does not send data faster than BARR/3270 can print or otherwise handle it. Values smaller than 7 often lower performance. This overrides the SRCVPAC value of LOGMODE.

PASSLIM=7

The maximum number of information frames sent to the physical unit at one time. This is usually set to the same value as MAXOUT.

VPACING=7

Similar to the PACING parameter. However, VPACING determines pacing between the 3174 establishment controller and VTAM. Values less than 7 lower efficiency.

BARR/3270 uses these system default values:

DISCNT=(NO,F)

The physical unit is not to be disconnected until requested by BARR/3270.

ISTATUS=ACTIVE

The physical unit will be activated automatically.

PUTYPE=2

BARR/3270 uses the Physical Unit Type 2 protocol.

Other useful parameters:

DLOGMOD=default_logon_mode_table_entry_name

Names the logmode table entry to be used by default. See Appendix D for 3270 DLOGMOD examples.

MODETAB=mode_table_name

The file of logmode entries. ISTINCLM is the default IBM-supplied mode table that is usually present with VTAM.

SSCPFM=USSSCS

Indicates that BARR/3270ís Logon Type is character coded.

LU Macro

The LU macro instructions define logical units. The logical units are allocated to the 3270 sessions.

Optimally, you will allocate as many logical units as sessions to be in use at the same time. Each unit requires a separate LU macro instruction. The number of LUs needed is the number of 3270 sessions.

Parameters BARR/3270 needs:

luname_i

The LU name conforms to your installationís naming convention. BARR/3270 does not use this name.

LOCADDR=i

The local addresses need to be unique and i not greater than 20.

5.3.2 SDLC Dedicated Line

Dedicated point-to-point lines operate at speeds from 4,800 to 384,000 bps. Dedicated lines are either leased from a phone company or installed by the end user in a single building or campus.

The SDLC Dedicated Line screen lists all the parameters needed by the BARR/3270 program and by VTAM and NCP on the mainframe. These parameters, which are entered into the host VTAM and NCP libraries, should be provided by the host communications programmer. After the Communication Link has been completed, BARR/3270 produces the statements that are entered into the VTAM and NCP parameter libraries.

NCP Parameters

The NCP parameters are specified by the LINE macro.

LINE Macro

NRZI=YES|NO

Non Return to Zero Inverted (NRZI) is a method of coding binary data with RS232 interface. Historically, there was reason to use it; at present its use relies on the convention of the host.

YES Use Non Return to Zero Inverted coding.

NO Do not use NRZI coding.

VTAM Parameters

The 3270 workstation corresponds to a Physical Unit (PU) in VTAM. The physical unit consists of 2 to 20 Logical Units (LU). The VTAM parameters are specified by the PU Macro and LU Macro.

PU Macro

ADDR=aa

Is the 8-bit address used by SDLC. This address, the first byte of every frame, separates messages sent to different physical units on the same line.

DATMODE=HALF|FULL

HALF In half duplex, the communications line is always either in a send or receive mode. Less than half the capacity of the line is available for use.

FULL Data is sent and received at the same time, resulting in twice the throughput. Some modems do not support full-duplex communication.

MAXDATA=265|521|1033

The maximum amount of data that can be sent on the physical unit in one frame. This count includes 9 bytes for header information plus the data length.

MAXOUT=n

Specifies that up to n frames may be sent by the SDLC protocol without pausing for a response. SDLC usually uses modulo 8 sequence numbers; MAXOUT=7 is optimal.

BARR/3270 also supports SDLC modulo 128 sequence numbers. This allows up to 127 SDLC frames to be sent before receiving a response; modulo 8 allows up to 7 SDLC frames. Modulo 128 works in half or full duplex. MAXOUT greater than 7 selects the Modulo 128 SDLC frame counts. The host definition must also include MODULO=128 in the NCP LINE macro. MAXOUT values for the host and BARR/3270 should match.

Set PACING, VPACING, and PASSLIM parameters of the NCP PU macro 1 greater than MAXOUT or the line will not operate optimally. For a further discussion of MAXOUT, see the later section Satellite Links and MAXOUT. NCP Definition for Dedicated Line.

After pressing ENTER, the following screen will appear.

Press any key.

Selected NCP parameters are described below for reference. The parameters are divided into three groups: parameters that are especially important to BARR/3270, parameters that use system defaults, and other options that users commonly reset.

GROUP Macro

The GROUP macro instruction gives common settings for all parameters for line macros within the group.

Parameters BARR/3270 needs:

group

The name of a GROUP macro instruction is not used by VTAM or by BARR/3270; it can be altered.

DIAL=NO

This is a dedicated line.

LNCTL=SDLC

The line control is SDLC.

LINE Macro

The form of the instruction is:

Parameters BARR/3270 needs:

linename

The VTAM name of the communications line.

ADDRESS=(aaa,FULL)

aaa Specifies the line interface address aaa.

DUPLEX=FULL

The line and modem can send and receive data simultaneously.

NRZI=YES|NO

Non Return to Zero Inverted (NRZI) is a method of coding binary data with RS232 interface; recommended if a high number of SDLC Aborts are experienced. Historically, there was reason to use it; at present its use relies on the convention of the host.

YES Use Non Return to Zero Inverted coding.

NO Do not use NRZI coding.

RETRIES=(8,2,20)

Specifies the number of attempts to recover from communications errors. The general form is:

RETRIES=(m,t,n)

m Maximum retransmissions of frame while waiting for normal response

t Time in seconds paused after m retransmissions failed

n Number of times the above error recovery sequence is repeated

SPEED=nnnnnn

Must be specified. Since the modem provides the bits-per-second clock, this parameter has no effect on the functioning of BARR/3270. However, the IBM Network Performance Monitor uses this value to calculate statistics.

TRANSFR=16

Specifies the number of NCP buffers corresponding to the maximum amount of data (the data transfer limit) that the NCP is to receive from the line during a single data transfer operation.

BARR/3270 uses these system default values:

CHECK=NODCD

Specifies that the Data Carrier Detect line from the modem is not to be monitored.

CLOCKNG=EXT

External clocking indicates that the modemís clock will control the transmission rate.

SERVICE Macro

The SERVICE macro controls the order in which the physical units are serviced on a dedicated line, for example:

service

The name of the SERVICE instruction is arbitrary, and you can have multiple SERVICE statements with the same name.

ORDER=(puname)

The operands in the ORDER list give the order in which the physical units will be polled on a multipoint line. You can preferentially service one of the physical units on a multipoint line by listing it more than once in the ORDER list.

PU Macro

The PU macro names and describes a physical unit. Several physical units can be operated on the same line (multipoint).

Each unit requires a separate PU macro instruction.

Parameters BARR/3270 needs:

puname

The physical unitís name conforms to your installationís naming convention. The VTAM operator uses the name to vary the unit as active or inactive and to query the unitís status.

ADDR=aa

Is the 8-bit address used by SDLC. This address, the first byte of every frame, separates messages sent to different physical units on the same line.

DATMODE=HALF|FULL

HALF In half duplex, the communications line is always either in a send or receive mode. Less than half the capacity of the line is available for use.

FULL Data is sent and received at the same time, resulting in twice the throughput. The V.32 modem standard supports full duplex on dial-up lines. Some modems do not support full-duplex communication.

MAXDATA=265|521|1033

The maximum amount of data that can be sent on the physical unit in one frame. This count includes 9 bytes for header information plus the data length.

MAXOUT=n

Specifies that up to n frames may be sent by the SDLC protocol without pausing for a response. SDLC usually uses modulo 8 sequence numbers; MAXOUT=7 is optimal.

BARR/3270 also supports SDLC modulo 128 sequence numbers. This allows up to 127 SDLC frames to be sent before receiving a response; modulo 8 allows up to 7 SDLC frames. Modulo 128 works in half or full duplex. MAXOUT greater than 7 selects the Modulo 128 SDLC frame counts. The host definition must also include MODULO=128 in the NCP LINE macro. MAXOUT values for the host and BARR/3270 should match.

Set PACING, VPACING, and PASSLIM parameters of the NCP PU macro to match MAXOUT or the line will not operate efficiently.

For a further discussion of MAXOUT, see the next section, Satellite Links and MAXOUT.

PACING=n

Determines how much data is sent to BARR/3270 before a pacing response is needed to send more data. Pacing is a flow control mechanism so that the mainframe does not send data faster than BARR/3270 can print or otherwise handle it. Values smaller than the MAXOUT parameter often lower performance.

PASSLIM=n

The maximum number of information frames sent to the physical unit at one time. This is usually set to the same value as MAXOUT.

VPACING=n

Similar to the PACING parameter. However, VPACING determines pacing between the 3174 establishment controller and VTAM. This is usually set to the same value as MAXOUT.

BARR/3270 uses these system default values:

DISCNT=(NO,F)

The physical unit is not to be disconnected until requested by BARR/3270.

ISTATUS=ACTIVE

The physical unit will be activated automatically.

PUTYPE=2

BARR/3270 uses the Physical Unit Type 2 protocol.

Other useful parameters:

DLOGMOD=default_logon_mode_table_entry_name

Names the Logon Mode Table Entry to be used by default. See Appendix D for 3270 DLOGMOD examples.

MODETAB=mode_table_name

The file of logmode entries. ISTINCLM is the default IBM-supplied mode table that is usually present with VTAM.

SSCPFM=USSSCS

Indicates that BARR/3270ís Logon Type is character coded.

LU Macro

The LU macro instructions define logical units. The logical units are allocated to the 3270 sessions.

Optimally, you will allocate as many logical units as sessions to be in use at the same time. Each unit requires a separate LU macro instruction. The number of LUs needed is the number of 3270 sessions.

Parameters BARR/3270 needs:

luname_i

The LU name conforms to your installationís naming convention. BARR/3270 does not use this name.

LOCADDR=i

The local addresses need to be unique and i not greater than 20.

Satellite Links and MAXOUT

Modulo 128 is normally useful only for satellite links. Satellite links introduce an average one-way delay of 0.4 seconds (IBM GG24-1629-1, pp. 43-44), or a round-trip delay of 0.8 seconds.

Delays with half duplex For a half-duplex link, every time a station finishes sending and enters Receive mode, you will not see the response from the other station begin until at least 0.8 seconds have passed; this wasted time is called line turnaround delay. Consider a 56Kb modulo 8 link using 521-byte SNA frames. Only 7 frames can be sent at one time and it takes about 0.5 seconds for them to be transmitted; then there is a 0.8-second turnaround delay. This means the line is idle 60 percent of the time. Using modulo 128 and increasing MAXOUT to 20 reduces the proportion of idle time to about 35 percent. Because line turnaround delays are so large, satellite links should be full duplex whenever possible.

Delays with full duplex Although a full-duplex link has no line turnaround, using the link at full efficiency requires that the acknowledgment for frame number N always be received before frame number N+MAXOUT is sent. For a 56Kb modulo 8 link using 521-byte SNA frames in full duplex, the 7 frames are sent in 0.5 seconds. It takes 0.8 seconds for the response to the first one to return, so there are times when the sender must wait. Using modulo 128 and increasing MAXOUT to 14 allows responses to be received with 0.2 seconds to spare.

Choosing MAXOUT for full duplex

The value for MAXOUT is a tradeoff between link efficiency, error recovery overhead, and memory requirements. For a full-duplex satellite link, MAXOUT should be slightly larger than the smallest value that allows frames to be acknowledged before MAXOUT is reached. While not exact, this formula is a guide:

MAXOUT = (0.8sec*baudrate/8/(MAXDATA+6))+5

0.8 sec = the round-trip satellite delay

baudrate = the speed of the line

8 = the number of bits in a byte

MAXDATA = the average size of link frames (often given by MAXDATA on the PU macro)

6 = the size of the SDLC header and trailer

5 = a safety factor

If MAXOUT is too small, the sender must wait for acknowledgments, thus reducing the efficiency of the line. If MAXOUT is too large, error recovery is unaffected but the memory required by BARR/3270 and the host communications controller increases. PACING and VPACING should be set to the same value as MAXOUT.

Choosing MAXOUT for half duplex

For a half-duplex satellite link, the choice is more difficult. A larger MAXOUT reduces the proportion of time lost to turnaround delay, but it can never eliminate the turnaround delay entirely. A large MAXOUT increases the number of frames that must be re-sent to recover from an error; the average number of frames re-sent per error is MAXOUT/2. The overhead for line turnaround must be balanced against the overhead for error recovery. Finally, a large MAXOUT increases the memory requirements for BARR/3270 and the host communications controller.

If you are attached to a satellite link via a Hughes Personal Earth Station, neither modulo 128 nor full duplex SDLC can be used because of the design of the Earth Station. MAXOUT and PASSLIM should be set to 7. However, you should set PACING and VPACING as if this were a modulo 128 full-duplex link.

Problems

You can tell whether you are operating in modulo 8 or modulo 128 mode by watching the Communication Scope. At the beginning of Logon the host sends Snrm for a modulo 8 link and Snre for a modulo 128 link. If you do not change the host definition to specify modulo 128, Snrm is displayed and only 7 frames at a time can be sent in either direction.

If the host definition is correct but you do not increase MAXOUT in the 3270 Description, Snre is displayed and data will flow correctly from the host to BARR/3270; however, BARR/3270 will only send 7 frames at a time to the host.

A large MAXOUT increases the amount of memory BARR/3270 uses for buffers. Symptoms of low memory include magenta Q or green Rnr on the Communication Scope or the message:

More memory needed for buffers

on the BARR/3270 console. You can also monitor the number of free buffers interactively from the Communications Statistics screen; always keep at least 25 buffers free. Increase BARR/3270 buffer memory from the Additional Parameters screen; a good start is an increase of MAXOUT*1024.

5.3.3 Token Ring Connection with 3725 & 3745 Controllers

The 3725 and 3745 communication controllers are attached to a Token Ring Network by use of a Token Ring Interface Coupler, (TIC). The 3725 & 3745 Controller screen lists all the parameters needed by the BARR/3270 program and by VTAM and NCP on the mainframe. These parameters, which are entered into the host VTAM and NCP libraries, should be provided by the host communications programmer. After the Communication Link has been completed, BARR/3270 produces the exact statements that are entered into the VTAM and NCP parameter libraries.

Token Ring Address Parameters

Each physical connection to the Token Ring Network has a unique address. This includes the mainframe TIC or the PC Token Ring Network adapters.

LOCADD=4000abbbbbbb

Specifies the address of the host Token Ring Interface Coupler (TIC) where a can be a number 0-7 and b can be a number 0-9.

VTAM Parameters

The 3270 workstation corresponds to a Physical Unit (PU) in VTAM. The physical unit consists of 2 to 20 Logical Units (LU). The VTAM parameters are specified by the PU Macro and LU Macro.

PU Macro

IDBLK=bbb
IDNUM=nnnnn

Parameters used on a switched line to identify the remoteís physical unit definition. The mainframe sends an Xid as the first message to a dial-up remote. The remote responds with an Xid that contains the IDBLK and IDNUM parameters.

VTAM searches for the physical unit identified by IDNUM and IDBLK. This physical unit is then used for the remainder of the communications session.

MAXDATA=265|521|1033

The maximum amount of data that can be sent on the physical unit in one frame. This count includes 9 bytes for header information plus the data length.

NCP Definition for 3725 & 3745 Controllers

After pressing ENTER, the following screen will appear.

Press any key.

Selected NCP parameters are described below for reference. The parameters are divided into three groups: parameters that are especially important to BARR/3270, parameters that use system defaults, and other options that users commonly reset.

GROUP Macro for Physical Group

Parameters BARR/3270 needs:

group

Group name, which can be changed.

ECLTYPE=PHYSICAL

This GROUP macro defines a physical connection to the Token Ring.

LINE Macro

Parameters BARR/3270 needs:

linename

Line name, which can be changed.

ADDRESS=(aaaa,FULL)

The logical address of the TIC in the NCP is aaaa.

LOCADD=4000abbbbbbb

The locally administered address for the TIC where a is a digit 0-7 and b is a digit 0-9.

PORTADD=pp

The port number pp that associates a physical line to a logical line. The number must be the same as the PHYPORT parameter on the logical line.

RCVBUFC=4095

This sets the maximum amount of data that can be received from the Token Ring Link.

GROUP Macro for Logical Group

Parameters BARR/3270 needs:

group

Group name, which can be changed.

ECLTYPE=LOGICAL

This GROUP macro defines a logical connection to the Token Ring.

AUTOGEN=100

The number of lines and groups supported by NCP.

CALL=INOUT

Both VTAM and BARR/3270 can initiate the connection.

PHYPORT=pp

The port number pp that associates a physical line to a logical line. The number must be the same as the PORTADD parameter on the physical line.

PU Macro

The PU macro names and describes a physical unit. This PU macro is replaced at Logon with the PU macro that is stored in VTAM.

Parameters BARR/3270 needs:

puname

The physical unitís name conforms to your installationís naming convention. The VTAM operator uses the name to vary the unit as active or inactive and to query the unitís status.

MAXLU=n

The only important parameter of this PU is the maximum number of LUs that will ever be used with this line.

Physical Unit Definition of 3725 & 3745 Controllers

After pressing any key, the following screen will appear.

Press any key.

Selected parameters are described below for reference. The parameters are divided into three groups: parameters that are especially important to BARR/3270, parameters that use system defaults, and other options that users commonly reset.

PU Macro

The PU macro names and describes a physical unit.

Parameters BARR/3270 needs:

puname

The physical unitís name conforms to your installationís naming convention. The VTAM operator uses the name to vary the unit as active or inactive and to query the unitís status.

ADDR=01

Required.

IDBLK=bbb
IDNUM=nnnnn

Parameters used on a Token Ring Network to identify the remoteís physical unit definition. The mainframe sends an Xid as the first message to a dial-up remote. The remote responds with an Xid that contains the IDBLK and IDNUM parameters. VTAM searches for the physical unit identified by IDBLK and IDNUM. This physical unit is then used for the remainder of the communications session.

PACING=7

Determines how much data is sent to BARR/3270 before a pacing response is needed to send more data. Pacing is a flow control mechanism so the mainframe does not send data faster than BARR/3270 can print or otherwise handle it. Values smaller than 7 often lower performance.

PASSLIM=7

The maximum number of information frames sent to the physical unit at one time.

VPACING=7

Similar to the PACING parameter. However, VPACING determines pacing between the 3174 establishment controller and VTAM. Values less than 7 lower efficiency.

BARR/3270 uses these system default values:

DISCNT=(NO,F)

The physical unit is not to be disconnected until requested by BARR/3270.

ISTATUS=ACTIVE

The physical unit will be activated automatically.

PUTYPE=2

BARR/3270 uses the Physical Unit Type 2 protocol.

Other useful parameters:

DLOGMOD=default_logon_mode_table_entry_name

Names the Logon Mode Table Entry to be used by default. See Appendix D for 3270 DLOGMOD examples.

MODETAB=mode_table_name

The file of logmode entries. ISTINCLM is the default IBM-supplied mode table that is usually present with VTAM.

SSCPFM=USSSCS

Indicates that BARR/3270ís Logon Type is character coded.

LU Macro

The LU macro instructions define logical units. The logical units are allocated to the 3270 sessions.

Optimally, you will allocate as many logical units as sessions to be in use at the same time. Each unit requires a separate LU macro instruction. The number of LUs needed is the number of 3270 sessions.

Parameters BARR/3270 needs:

luname_i

The LU name conforms to your installationís naming convention. BARR/3270 does not use this name.

LOCADDR=i

The local addresses need to be unique and i not greater than 20.

5.3.4 Token Ring Connection with Local 3174

The IBM 3174 Establishment Controller is a departmental communication controller that supports connection to a Token Ring Network with a Token Ring adapter. The 3174 is sometimes called a cluster controller for 3270 coax-attached terminals. The Local 3174 is channel attached to the mainframe. The Remote 3174 is connected by a communication line to the mainframe 3720, 3725, or 3745 (communication controller). This section describes the Local 3174.

The Local 3174 screen lists all the parameters needed by the BARR/3270 program and by VTAM and NCP on the mainframe. These parameters, which are entered into the host VTAM and NCP libraries, should be provided by the host communications programmer. After these parameters have been entered, BARR/3270 produces the exact statements that are placed into the VTAM and NCP parameter libraries.

Token Ring Address Parameters

Each physical connection to the Token Ring Network has a unique address. This includes the mainframe or the PC Token Ring Network adapters. The 3174 Configuration Question 904 (Ring Address Assignment) defines this information.

LOCADD=4000abbbbbbb

Specifies the locally administered address of the 3174 Token Ring adapter where a can be a number 0-7 and b can be a number 0-9.

VTAM Parameters

The 3270 workstation corresponds to a Physical Unit (PU) in VTAM. The physical unit consists of 2 to 20 Logical Units (LU). The VTAM parameters are specified by the PU Macro and LU Macro.

PU Macro

CUADDR=ccc

Channel Unit Address, ccc, is the channel and unit address of the 3174 on the S/370 I/O channel.

MAXDATA=265|521|1033

The maximum amount of data that can be sent on the physical unit in one frame. This count includes 9 bytes for header information plus the data length.

Physical Unit Definition of Local 3174

After pressing any key, the following screen will appear.

Press any key.

Selected parameters are described below for reference. The parameters are divided into three groups: parameters that are especially important to BARR/3270, parameters that use system defaults, and other options that users commonly reset.

PU Macro

The PU macro names and describes a physical unit.

Parameters BARR/3270 needs:

puname

The physical unitís name conforms to your installationís naming convention. The VTAM operator uses the name to vary the unit as active or inactive and to query the unitís status.

CUADDR=ccc

Channel Unit Address, ccc, is the channel and unit address of the 3174 on the S/370 I/O channel.

SECNET=YES

The physical unit is associated with a secondary network.

MAXBFRU=8

The number of receive buffers used by VTAM.

MAXDATA=265|521|1033

The maximum amount of data that can be sent on the physical unit in one frame. This count includes 9 bytes for header information plus the data length.

PACING=7

Determines how much data is sent to BARR/3270 before a pacing response is needed to send more data. Pacing is a flow control mechanism so the mainframe does not send data faster than BARR/3270 can print or otherwise handle it. Values smaller than 7 often lower performance.

VPACING=7

Similar to the PACING parameter. However, VPACING determines pacing between the 3174 establishment controller and VTAM. Values less than 7 lower efficiency.

BARR/3270 uses these system default values:

DISCNT=(NO,F)

The physical unit is not to be disconnected until requested by BARR/3270.

ISTATUS=ACTIVE

The physical unit will be activated automatically.

PUTYPE=2

BARR/3270 uses the Physical Unit Type 2 protocol.

Other useful parameters:

DLOGMOD=default_logon_mode_table_entry_name

Names the Logon Mode Table Entry to be used by default. See Appendix D for 3270 DLOGMOD examples.

MODETAB=mode_table_name

The file of logmode entries. ISTINCLM is the default IBM-supplied mode table that is usually present with VTAM.

SSCPFM=USSSCS

Indicates that BARR/3270ís Logon Type is character coded.

LU Macro

The LU macro instructions define logical units. The logical units are allocated to the 3270 sessions.

Optimally, you will allocate as many logical units as sessions to be in use at the same time. Each unit requires a separate LU macro instruction. The number of LUs needed is the number of 3270 sessions.

Parameters BARR/3270 needs:

luname_i

The LU name conforms to your installationís naming convention. BARR/3270 does not use this name.

LOCADDR=i

The local addresses need to be unique and i not greater than 20.

5.3.5 Token Ring Connection with Remote 3174

The IBM 3174 Establishment Controller is a departmental communication controller that supports connection to a Token Ring Network with a Token Ring adapter. The 3174 is sometimes called a cluster controller for 3270 coax-attached terminals. The Local 3174 is channel attached to the mainframe. The Remote 3174 is connected by a communication line to the mainframe 3720, 3725, or 3745 communication controller. This section describes the Remote 3174.

The Remote 3174 screen lists all the parameters needed by the BARR/3270 program and by VTAM and NCP on the mainframe. These parameters, which are entered into the host VTAM and NCP libraries, should be provided by the host communications programmer. After the Communication Link has been completed, BARR/3270 produces the exact statements that are entered into the VTAM and NCP parameter libraries.

Token Ring Address Parameters

Each physical connection to the Token Ring Network has a unique address. This includes the mainframe or the PC Token Ring Network adapters. The 3174 Configuration Question 904 (Ring Address Assignment) defines this information.

LOCADD=4000abbbbbbb

Specifies the locally administered address of the 3174 Token Ring adapter where a can be a number 0-7 and b can be a number 0-9.

NCP Parameters

The NCP parameters are specified by the LINE macro.

LINE Macro

NRZI=YES|NO

Non Return to Zero Inverted (NRZI) is a method of coding binary data with RS232 interface. Historically, there was reason to use it; at present its use relies on the convention of the host.

YES Use Non Return to Zero Inverted coding.

NO Do not use NRZI coding.

VTAM Parameters

The 3270 workstation corresponds to a Physical Unit (PU) in VTAM. The physical unit consists of 2 to 20 Logical Units (LU). The VTAM parameters are specified by the PU Macro and LU Macro.

PU Macro

ADDR=aa

Is the 8-bit address used by SDLC. This address, the first byte of every frame, separates messages sent to different physical units on the same line.

MAXDATA=265|521|1033

The maximum amount of data that can be sent on the physical unit in one frame. This count includes 9 bytes for header information plus the data length.

NCP Definition for Remote 3174

After pressing ENTER, the following screen will appear.

Press any key.

Selected NCP parameters are described below for reference. The parameters are divided into three groups: parameters that are especially important to BARR/3270, parameters that use system defaults, and other options that users commonly reset.

GROUP Macro

The GROUP macro instruction gives common settings for all parameters for line macros within the group.

Parameters BARR/3270 needs:

group

The name of a GROUP macro instruction is not used by VTAM or by BARR/3270; it can be altered.

DIAL=NO

This is a dedicated line.

LNCTL=SDLC

The line control is SDLC.

LINE Macro

The form of the instruction is:

Parameters BARR/3270 needs:

linename

The VTAM name of the communications line.

ADDRESS=(aaa,FULL)

Specifies the line interface address.

DUPLEX=FULL

The line is capable of sending and receiving at the same time.

NRZI=YES|NO

Non Return to Zero Inverted (NRZI) is a method of coding binary data with RS232 interface. Historically, there was reason to use it; at present its use relies on the convention of the host.

YES Use Non Return to Zero Inverted coding.

NO Do not use NRZI coding.

RETRIES=(8,2,20)

Specifies the number of attempts to recover from communications errors. The general form is:

RETRIES=(m,t,n)

m Maximum retransmissions of frame while waiting for normal response

t Time in seconds paused after m retransmissions failed

n Number of times the above error recovery sequence is repeated

SPEED=nnnnnn

Must be specified. Since the modem provides the bits-per-second clock, this parameter has no effect on the functioning of BARR/3270. However, the IBM Network Performance Monitor uses this value to calculate statistics.

TRANSFR=16

Specifies the number of NCP buffers corresponding to the maximum amount of data (the data transfer limit) that the NCP is to receive from the line during a single data transfer operation.

BARR/3270 uses these system default values:

CHECK=NODCD

Specifies that the Data Carrier Detect line from the modem is not to be monitored.

CLOCKNG=EXT

External clocking indicates that the modemís clock will control the transmission rate.

SERVICE Macro

The SERVICE macro controls the order in which the physical units are serviced on a dedicated line, for example:

service

The name of the SERVICE instruction is arbitrary, and you can have multiple SERVICE statements with the same name.

ORDER=(puname)

The operands in the ORDER list give the order in which the physical units will be polled on a multipoint line. You can preferentially service one of the physical units on a multipoint line by listing it more than once in the ORDER list.

PU Macro

The PU macro names and describes a physical unit. Several physical units can be operated on the same line (multipoint). Each unit requires a separate PU macro instruction.

Parameters BARR/3270 needs:

puname

The physical unitís name conforms to your installationís naming convention. The VTAM operator uses the name to vary the unit as active or inactive and to query the unitís status.

ADDR=aa

Is the 8-bit address used by SDLC. This address, the first byte of every frame, separates messages sent to different physical units on the same line.

MAXDATA=265|521|1033

The maximum amount of data that can be sent on the physical unit in one frame. This count includes 9 bytes for header information plus the data length.

MAXOUT=n

Specifies that up to n frames may be sent by the SDLC protocol without pausing for a response. SDLC usually uses modulo 8 sequence numbers; MAXOUT=7 is optimal and is the maximum.

Set PACING, VPACING, and PASSLIM parameters of the NCP PU macro to match MAXOUT or the line will not operate efficiently.

PACING=n

Determines how much data is sent to BARR/3270 before a pacing response is needed to send more data. Pacing is a flow control mechanism so that the mainframe does not send data faster than BARR/3270 can print or otherwise handle it. Values smaller than the MAXOUT parameter often lower performance.

PASSLIM=n

The maximum number of information frames sent to the physical unit at one time. This is usually set to the same value as MAXOUT.

VPACING=n

Similar to the PACING parameter. However, VPACING determines pacing between the 3174 establishment controller and VTAM. This is usually set to the same value as MAXOUT.

BARR/3270 uses these system default values:

DATMODE=HALF

Required by 3174.

DISCNT=(NO,F)

The physical unit is not to be disconnected until requested by BARR/3270.

ISTATUS=ACTIVE

The physical unit will be activated automatically.

PUTYPE=2

BARR/3270 uses the Physical Unit Type 2 protocol.

Other useful parameters:

DLOGMOD=default_logon_mode_table_entry_name

Names the Logon Mode Table Entry to be used by default. See Appendix D for 3270 DLOGMOD examples.

MODETAB=mode_table_name

The file of logmode entries. ISTINCLM is the default IBM-supplied mode table that is usually present with VTAM.

SSCPFM=USSSCS

Indicates that BARR/3270ís Logon Type is character coded.

LU Macro

The LU macro instructions define logical units. The logical units are allocated to the 3270 sessions.

Optimally, you will allocate as many logical units as sessions to be in use at the same time. Each unit requires a separate LU macro instruction. The number of LUs needed is the number of 3270 sessions.

Parameters BARR/3270 needs:

luname_i

The LU name conforms to your installationís naming convention. BARR/3270 does not use this name.

LOCADDR=i

The local addresses need to be unique and i not greater than 20.

5.3.6 Gateway Connections with NETBIOS

Since the Network Basic Input/Output System (NETBIOS) software interface to a LAN was introduced by IBM, NETBIOS has become an industry standard implemented by almost all vendors of LAN adapters, including Ethernet, Arcnet, and Token Ring.

While NETBIOS is a universal interface, the software adds memory and takes 30 seconds to make a link connection.

Workstation name

The name unique to the LAN that is used to identify your workstation. This name can also be supplied at the DOS prompt by entering

BARRSNAR #username

Gateway name

The name of the gateway with which you are communicating. The default name BARRGATE is usually used.

5.3.7 Gateway Connections with Novell IPX

The Novell IPX is efficient and already present if you have a Novell LAN. This LAN software interface has been implemented for all LAN adapters, including Ethernet, Arcnet, and Token Ring.

Workstation name

The name unique to the LAN that is used to identify your workstation. This name can also be supplied at the DOS prompt by entering

BARRSNAR #username

If the name is left blank, the Novell user name is used.

Gateway name

The name of the gateway with which you are communicating. The default name BARRGATE is usually used.

5.3.8 Gateway Connections with Token Ring Address

The Token Ring software interface is used by the IBM LAN Support program. This interface is available for all Token Ring adapters. The IBM LAN Support program 1.2 also supports Ethernet adapters.

Gateway Token Ring Address

This corresponds to the Token Ring address of the PC running BARR/GATE. Enter the address shown on the BARR/GATE console. You can also find out the address by running the TRN_ADDR program.

5.4 Devices and Printers

Devices and printers can be attached to your PC using a parallel port or a serial port. From the Devices and Printers screen, you tell BARR/3270 what types of devices or printers you have attached to these ports on your PC.

Ports

The DOS names for the parallel printer ports are LPT1, LPT2, and LPT3. The DOS names for the serial ports are COM1 and COM2. BARR/3270 asks the same set of questions about each one of these devices. Chapter 9 further describes printer capabilities.

The program repeats the procedure for every device.

From the Installation Description screen, select Devices and Printers: LPT1, LPT2, LPT3, COM1, COM2.

The screen gives the status of each of the devices. The BARR/3270 default is set up for one printer.

Select LPT1. (If you select COM1 or COM2, the Serial port options will also be displayed on the screen.)

Select Choose printer type.

Choose Printer Type

On every printer, you can manually set lines-per-inch. As an alternative to manually making these adjustments, BARR/3270 automatically sets the lines-per-inch for you if you use one of the printers listed on this screen.

Select printer type (in this example, DAVFU, Dataproducts).

For the Printronix P300, P600, or the DAVFU, Dataproducts option, the lines-per-inch is not set.

Miscellaneous Printer Options

You may want to use the Miscellaneous Printer Options if you are having problems with the printer. Use these options to simplify the processing of the print stream or to specify the Printer Timing Delay.

Press ENTER to return to the Devices and Printers screen.

Select Miscellaneous Printer Options.

Printer performance optimized?

Yes Default. Printer performance will be altered as follows:

No Data will be sent directly to the printer.

Conditional new page at end of file?

Yes Default. At the end of a file, if the print head is not already at the top of a page, form feed the paper. If the next file begins with a form feed, take out the form feed to prevent printing a blank page.

No Do not put a new page at the end of a file, and do not remove a form feed from the beginning of the file.

Make all files have an even number of pages?

No Default. Number of printed pages may be even or odd.

Yes Have the job header page always face up on the fan-fold paper stack. Make print files an even number of pages if they are received as an odd number of pages.

Printer timing delay:

Some printers are unable to accept data as fast as BARR/3270 can send it. BARR/3270 will never send data to the printer if the busy line is active. However, some printers are slow in setting the busy line.

The default 8 is the desired setting for PC AT workstations using Dataproducts line printers. Change 8 to any number that gives the printer enough time to set the busy line. This option may be necessary with some forms that do not have a 1 as the first position of the VFU.

This parameter should be 0 if a BARR/DPI adapter is used.

The Printer Timing Delay rules out sending data faster than the printer can handle it. See IBM Technical Reference, Options and Adapters, Volume 1, Section Graphics Printer, for a description of the busy line. Overdriving the printer is impossible if you use this definition. Unfortunately, not all printers use this definition. We are always glad to assist you in tuning this parameter.

Audible alarm on printer error?

You will hear a shrill "beep" when an error or paper condition occurs. The noise will stop when you correct the condition or press the keyboard. This option applies only to parallel printers.

No No alarm.

Yes Alarm enabled.

Printer Control Data

Printer Control Data is an optional feature. The characters entered here are used to control special functions of the printer such as page size, lines-per-inch, characters-per-inch, typeface, and other printer features. You will enter the Printer Control Data in strings of characters, each terminated by 2 bytes of hex zeros (00 00).

Select Printer Control Data from the Devices and Printers screen.

Type hex data. Use the arrows to move around the screen.

(The ESC key returns the screen to its original values should you make an error.)

The first string entered at the start of the screen is sent to the printer at the start of the file.

Strings that start with the bytes 01 through FD are sent to the printer when referenced by the current form on the printer. This makes it possible to use the form to control landscape or portrait mode on a laser printer.

The string that starts with FF is sent to the printer at the end of a file.

Refer to your printer manual for the escape sequences required by your printer.

Xerox Example

This example describes the hex characters for the Xerox 2700. If the first byte of the Printer Control Data is given as 0C (the ASCII form feed character), the first byte of the print file received will be ignored if it is a form feed character. 1B 6F causes the offset stacker feature to be used at the start of every file received.

OKIDATA Example

Hex digits 1D cause the OKIDATA 92 and 93 printer to print in a compressed 132 character-per-line mode.

EPSON/IBM Example

Hex digits 0F cause the EPSON/IBM printer to print in a compressed 132 character-per-line mode.

EPSON/IBM Example

End-of-file string (selection character FF) is sent to the printer at the end of each file. In this example, hex digits 0F are sent to put the EPSON/IBM printer into compressed mode at the beginning of each file, and hex digits 12 are sent to put it into normal mode at the end of each file.

Serial Port Options

If you define devices and printers attached to COM1 or COM2, the Devices and Printers screen will display Serial Port Options. The mode (baud, parity, data bits, and stop bits) of the serial port must match the mode of the device attached to that serial port. Consult your device manual for the mode information.

Baud rate?

Baud rate (bits per second) determines the rate at which data bits are transmitted. The receiver and sender must transmit at the same rate. Possible choices are 110, 150, 300, 600, 1200, 2400, 4800, 9600, and 19.2K.

Parity?

A parity bit may be added to each transmitted character to aid in error detection. Choices for parity are None, Odd, and Even; this must be the same for both sender and receiver.

None No parity.

Odd Sum of 1 bits is odd.

Even Sum of 1 bits is even.

Data Bits?

This is the number of bits transmitted for each character. The number of data bits for sender and receiver must match.

8 Default. Eight bits are required for binary data.

7 Not usually used, although sufficient for 7-bit ASCII data.

Stop Bits?

Data travel on an RS232 line as a 1 or 0. The beginning of a data string is indicated by one start bit. The end of a character is indicated by one or two stop bits. Choose the number of stop bits required by the receiver.

1 Default. One stop bit will be used at end of character.

2 Two stop bits will be used at end of character.

Hardware flow control?

Flow control prevents congestion of data caused by one device transmitting data faster than another device can receive data. Some printers use XON/XOFF flow control, some use hardware flow control, and some use both. A printer that uses hardware flow control will use a signal on an RS232 pin to show that it is ready to receive data. The printer cable normally connects this signal to Clear-To-Send on the PCís serial port. See Section C.3 and Section C.4 for cable specifications.

CTS Default. Test Clear-To-Send (CTS) before sending data.

DSR Test Data-Set-Ready (DSR) before sending data.

DSR & CTS Test both Data-Set-Ready and Clear-To-Send before sending data. The status line will indicate which of the signals is low; if both are low, DSR=0 is used. DOS uses this method of flow control.

None Do not test CTS or DSR. Some printers donít use hardware flow control. They use only XON/XOFF flow control.

Appendix C Serial Port Interface documents serial port definitions for sending and receiving data.

You have selected the correct flow control option if the status line on the BARR/3270 Operation screen displays XOFF, CTS=0, or DSR=0 when you take the printer off line, and normal when you put the printer on line.

XON/XOFF flow control?

No XON/XOFF flow control will not be used to prevent congestion of data.

Yes Some plotters and printers use XON/XOFF flow control to prevent overrun on the data line when the printer or plotter is busy.

The XOFF character from the printer suspends output; XOFF is the ASCII DC3 character coded as hex 13.

XON resumes output to the printer. XON is the ASCII DC1 character coded as hex 11.

The flow control mechanism ignores the parity of XON and XOFF characters.

Use this device as a data Source as well as Destination?

No Serial port will only be used as Destination.

Yes Not applicable for BARR/3270.

5.5 Assign Devices

BARR/3270 sets up the Assign Devices screens according to the instructions you have given in the 3270 Description. The assignments can be as simple or as complex as you want them.

Assign Devices is not accessible if there are no printer sessions in the 3270 Description. The following section explains possible selections from the Assign Devices screen. Once you have become familiar with the Assign Devices screen by following the step-by-step instructions below, you need not follow the same order. Simply select the assignment you wish to modify.

Assignment Screen

The first two lines of the Assign Devices screen show the current status of the assignment. The number of printer sessions that you specified in the 3270 Description screen will also be reflected here.

Source/Destination Devices

When thinking about Sources and Destinations, you must think in relation to the BARR/3270 program. With this in mind, Source devices are where files flow into the program. Destination devices are the places those files exit from BARR/3270. Possible Sources and Destinations are listed in the following tables.

You can assign any Source device to any Destination device. The devices will appear on the Assign Devices screen as Sources or Destinations:

Sources

Sources appear to the left of the blinking arrow, which points toward the Destination to be modified.

The following Source is available:

PR_session

LU1 and LU3 printers. Source names for 3270 printers are prefixed with the string PR_. The first six non-blank characters of the session name are used as the suffix.

Destinations

Destinations are to the right of each arrow in the Assignment portion of the screen. The following are available Destinations:

(FILE)

Allows files to be put anywhere within the DOS file system, including the hard disk, floppy disk, local area network (LAN), or other Destination device.

SCREEN

The screen (monitor) attached to your PC. Screen scrolling is 4 lines per second. To pause the screen, press Scroll-Lock. For fast screen scrolling, press Scroll-Lock and 1. To slow the speed, press Scroll-Lock and 0.

NUL

Output sent to this Destination is discarded.

SUSPEND

A suspended device is held still (saved in memory). This prevents accidental loss of output.

LPT1-LPT3

Parallel ports. Centronics parallel printer interface ports. Print speed to 6000 lines per minute.

COM1-COM2

Serial ports. COM1 and COM2 are the RS232 asynchronous communications ports that operate at 110 to 19,200 bits per second. XON/XOFF, CTS, and DSR flow control are supported.

Only the devices (LPT1, LPT2, LPT3, COM1, or COM2) that you have chosen in Devices and Printers from the Installation Description will appear on the Assign Devices screen.

Example

A common use is to assign a printer session to the PC printer LPT1. The sequence of selecting Sources and Destinations is shown in the following screens.

Select the Source (in this example PR_TSO).

Select the Destination (in this example LPT1).

The screen will be changed to reflect your selection.

Assigning (FILE) as a Destination

A Destination can be a DOS file on disk. For example, you could direct a printer file from the host to a PC file on your hard disk. If you select (FILE) as a Destination, you will be requested to provide the file name.

A file name consists of a beginning of the file name and an ending of the file name. Both parts of the name are optional because the complete file name is a combination of them.

The extension to the file name is a period followed by up to three characters. If you do not specify a file extension, then a numeric extension will be assigned. The directory will be searched for that file name with a numeric extension. The extension N+1 will be assigned where N is the highest extension found. If no numeric extension is found on the directory, then extension .001 will be assigned. If the file name is followed by a period (.), a blank extension is implied.

Beginning of file name:

The beginning of the file name is specified on the following line.

Type beginning of file name or leave blank.

Ending of file name is:

Choice

Description

not used

Only option for BARR/3270.

Replace/Append/Print

This option controls whether a new file replaces the contents of an old file with the same name, the new file is appended to the end of the file, or printer control codes are written to a file.

Replace Replace contents of the old file with the same name.

Append Add contents of new file to end of old file.

Print Not available for BARR/3270.

Log/No Log

The Log/No Log option controls writing messages to the start and end of each file. Use this option when you want to unclutter the screen of redundant messages.

Log For each file written, write the Log messages:

WRITING:X.
CLOSE:X.

No Log Messages are not shown on the screen.

The following example illustrates the use of these options.

Example: PR_session output

You may want to save PR_session output on disk.

Select PR_session as Source.

Select (FILE) as Destination.

Type PRINT

The file name appears in parentheses as the Destination of PR1.

Because no extension is given in the file name, BARR/3270 assigns a 3-digit extension. If the numeric extension already exists, the next highest number will be used. If the file name is followed by a period (.), a blank extension is implied.

BARR/3270 sequentially creates the file name extensions

PRINT.001
PRINT.002

In this example, PRINT is the file name and 001 is the extension given to the first file. 002 is the extension given to the second file with the same name and so on for as many files as you have.

Continue

Selecting Continue allows you to assign another device.

Receive Mode

Receive mode controls handling of the printer files received from the host.

Select Receive mode.

Select a receive mode.

An asterisk appears in the assignment list when you select any options other than ASCII.

ASCII

Default receive mode. The EBCDIC file received is converted to an ASCII print file. See Appendix B.

Binary

Use this mode for files that you do not want translated from EBCDIC to ASCII. The data within the print or punch line is not translated. BARR/3270 ignores the carriage control information.

N ASCII lines

You can receive lines longer than 80 characters. The host uses a program to write a file with 1 to 9 lines of 80 characters for each record sent. BARR/3270 combines n records into a single ASCII record, n times 80 bytes long.

DOS file

Obsolete option. Transfer files now used.

Variable ASCII lines

BARR/3270 combines a variable number of 80-character lines into a single ASCII line. The appearance of a vertical line marks the end of the ASCII line. The vertical line and all characters to the right are ignored.

Fixed length

Records are written at a fixed length. The structure of the data remains the same as it was on the mainframe. The most common use of the fixed-length mode is for receiving files directed to a tape drive with BARR/TAPE support. In addition to the data within the record, the ASA carriage control character can be included as the first character of the fixed-length record. You can then receive your printout in a PRINT TAPE format.

Fixed-length parameters:

Block size Length of the maximum block written to tape.

Logical record length Total length of the record including the ASA carriage control character if present. The maximum length is 254.

Carriage control Two choices: none or ASA.

Character set

EBCDIC Selects EBCDIC character set.

EBCDIC variable Selects EBCDIC variable-length records, allowing binary data not to be padded with blanks when it is received on the PUNCH stream.

ASCII Selects ASCII character set.

ASCII with CR LF If you choose ASCII with CR LF for the Character Set parameter, each record will end with a Carriage Return and a Line Feed. The length of data in the record will be 2 less than the logical record length.

ASCII variable ASCII variable is the same as ASCII with CR LF except that trailing blanks are eliminated from the end of records.

S/370 Channel Choose S/370 Channel to output the file as varying length binary records using the Realia COBOL definitions. Each record is preceded by EBCDIC ASA carriage control (skip after printing). The FCBLOAD record is included in the file. This format is used to support the channel-attached printers from the PC.

With Carriage Control: None The carriage control in the output record is the carriage control received from the mainframe. Default.

With Carriage Control: ASA The carriage control in the output record is taken from the first position of the print record. This is useful when converting from the Xerox 871 to BARR RJE.

The last line gives the IBM JCL Data Control Block description that represents your selections.

Edit parameters. Use arrows to move around the screen. Press ENTER to keep changes and ESC to return to Receive Mode screen.

Transfer files

General file transfer between MVS operating system file structure and the PC file structure. See Chapter 11 File Transfer.

Press ESC again for Assign Devices.

Options

Type values.

OUTPUT statement used in file? No

The OUTPUT statement is used to provide JOBNAME, FORMNAME, FILENAME, COPIES, PRIORITY, and CLASS parameters for the output file.

No Indicates that an OUTPUT statement is not used.

Yes Not applicable to BARR/3270.

Ignore n lines from start of file.

Not applicable for BARR/3270.

Class=n

Use the Class=n option to assign a default output class to a file received on the Print or Punch stream.

5.6 Monitor and Adapter

BARR/3270 offers complete support for popular monitors and adapters. The Monitor and Adapter screen specifies the monitor type, adapter for the monitor, and screen sizes for the 3270 and DOS sessions. With many adapters you can specify a screen size larger than the 25x80 normally used on the PC; BARR 3270 supports the 43x80, 50x80, and the 44x132.

Monitor?

The type of monitor.

Default BARR/3270 program automatically decides whether the monitor is color or monochrome from the current MODE setting.

CGA A monitor that is compatible with the IBM Color Graphics Adapter.

EGA A monitor that is compatible with the IBM Enhanced Graphics Adapter.

VGA A monitor that is compatible with the IBM Video Graphics Array Adapter.

Monochrome Any monitor that has a two-color display.

Multiscan A monitor with multiple scan rates that automatically adjusts to the adapter scan rate. The most popular is the NEC MULTISYNC monitor.

Adapter?

The PC adapter that is connected to the monitor.

Default The default choice asks the program to determine the adapter type. The program will automatically determine if the adapter is the IBM Monochrome Display Adapter, IBM Color Graphics Adapter, IBM Enhanced Graphics Adapter, or the IBM Video Graphics Array Adapter. You will always be able to use BARR/3270 with Default. Choose your adapter type to take advantage of larger screen size.

Other choices:

Everex/EV-659
Paradise/VGA
Tseng EVA/480
VGA Wonder
Genoa SVGA/6300
US Video VGA
STB VGA EM-16
Tecmar VGA

OPER screen size?
DOS screen size?

The size of the OPER or DOS screen. If the screen size chosen is incompatible with the actual monitor or adapter, the screen size will be forced to a smaller size.

Choices are:

25x80
43x80
50x80
44x132

Some additional choices are available for specific adapters.

5.7 Modem Type and Dialing Instructions

BARR/3270 can automatically dial the host computer if you are using a PC-SYNC modem, a 2400 AT modem, or a Dataphone 2224B modem. For a complete description of the screen, consult your PC-SYNC manual.

If you are using an external modem, select Not autodial modem. This is the automatic selection made by BARR/3270 if PC-SYNC is not installed.

If your external modem can be programmed with the host phone number, the modem will automatically dial when it senses DTR from BARR/3270.

For convenience in using the BARR PC-SYNC modem, the following screens show how to enter the telephone number.

Select BARR PC-SYNC modem (automatically selected by BARR/3270 if you are using PC-SYNC).

If the first phone is busy, the next phone will be called. These options are explained in detail in your PC-SYNC or PC-SYNC/2 manual.

5.8 Startup Screen Notes

This screen shows optional, but helpful, information about your central host name and frequently called telephone numbers. The name and numbers you enter appear on the screen at startup.

Type information at the cursor. Replace Barr Systemsí definitions.

5.9 Interrupt Request, Address, and Loopback Test

Setting To reach the software setting, select Interrupt Request, Address, and Loopback Test from the Installation Description screen.

Select or type new settings.

The next screen shows a picture of the current setting on the BARR adapter or PC-SYNC modem.

If an error is detected, a warning or error message appears. Choose new settings that do not produce this message. Refer to your adapter manual if necessary.

Interrupt request?
Address?

The Interrupt Request (IRQ) and Device Address on the BARR adapters and PC-SYNC modems are preset. These same settings are specified in the BARR/3270 program. Please do not alter these settings unless a definite conflict exists.

A Device Address conflict rarely occurs. However, an IRQ conflict is not uncommon if you are using a Local Area Network adapter. LANs typically use IRQ2.

If you have a verified conflict with either IRQ or Device Address, you will need to alter the setting on the BARR adapter or PC-SYNC modem. See the BARR Adapter manual or PC-SYNC Modem manual for instructions on changing settings. You will then match that same setting in the BARR/3270 software. (If you are using the BARR/6BBB adapter, you will not need to modify these settingsóthe software locates the adapter and reads the address and Interrupt Request. However, if you have several adapters in one PS/2, you use the Device Address to choose between them.)

Use DMA for communications?

Direct Memory Access (DMA) is a time-honored way to achieve high transfer rates between memory and a peripheral device. Special hardware implements Direct Memory Access so that the software only has to initiate the transfer of a block of memory. Without DMA, software has to handle each byte of memory.

Yes Default. Speeds up to 256,000 bps are achieved on a PC AT or PS/2. DMA Requests 1 or 3 are used on PC, PC AT, or PS/2 Models 25 and 30. This option is ignored if you are using a PC-SYNC modem.

No DMA is not used. No selection may be necessary if another device is using Request 1 on PC or PC AT.

DMA request: 1|3|1&3

The choices are 1, 3, or 1&3. On the PC, PC AT, and PS/2 Models 25 and 30, DMA Requests 1 and 3 are available. Only DMA Request 1 is available on the PC XT. DMA Request 1&3 is used with full duplex when DATMODE=FULL is specified in the 3270 Description.

(If you are using the BARR/6BBB adapter, you will not need to modify this settingóthe software reads the DMA request from the adapter.)

Perform loopback test?

No Default.

Yes Performs a test to verify that the hardware and software settings and installation are correct. Run this test after hardware and software installation, whenever the settings on this screen are changed, or if a hardware error is suspected. The loopback test performs diagnostics of the synchronous adapter, cable, and modem. You will be instructed at each step.

BARR/3
BARR/6BBB

For the BARR/3 and BARR/6BBB adapters, the loopback test consists of two parts:

Loopback test of BARR adapter with BARR TEST plug

This part uses the BARR/3 or BARR/6BBB synchronous communications adapter with the TEST plug from Barr Systems. To run this comprehensive test of the adapter, insert the TEST plug, which comes strapped to the modem cable, into the adapter. The test does not involve the modem or modem cable; therefore, any problem reported is in the adapter.

Loopback test of BARR adapter with modem in analog loopback mode.

This part uses the BARR/3 or BARR/6BBB synchronous communications adapter cabled to an external modem, which is set to Analog Loopback Mode.

The test performs diagnostics of the cable and modem.

The PC sends data:

Since the modem is in loopback mode, data will not enter the telephone. Instead, the data will enter the receive side of the modem.

The data return:

PC-SYNC

Loopback test for PC-SYNC and PC-SYNC/2 modems

The PC-SYNC modem has an extensive internal self-test procedure built in. It will verify correct operation of almost every feature. The send and receive loopback tests are much more rigorous than those of external modems because they can internally introduce weak and distorted signals to test the automatic error compensation circuits. The test is so thorough that a PC-SYNC modem may occasionally fail self-test, but function fine under normal conditions.

Test Result

Several tests appear on the screen before the program reports the test results.

BARR/3270 notifies pass/fail of the test.

or

or

Return modem to NORMAL mode.

Press any key. The Interrupt Request, Address, and Loopback Test screen returns to Installation Description.

If test fails, BARR/3270 notifies you of probable cause. Check the following:

  1. Is the adapter installed correctly?

  2. Conflicting Interrupt Request usage. Is another adapter using this interrupt request? If so, follow the instructions earlier in this section to reset IRQ. The BARR/3270 software and adapter settings must match.

  3. Is the device address specified in the program the same as the jumper settings on the BARR adapter? If so, follow the instructions earlier in this section to reset Device Address. The BARR/3270 software and adapter settings must match.

  4. Is the modem cable connected correctly? Standard async modem cables do not work because pins 15 or 17 are not connected.

  5. Is the modem set in analog loopback mode? If not, set the modem to AL.

5.10 Tuning Data

Tuning Data parameters are not relevant for most customers. Select this option only if you need to change the configuration data. Chapter 6 describes Tuning Data.

5.11 Exit and Save Changes

Select Exit and Save Changes when you have finished installing BARR/3270. BARR/3270 will then permanently update the Installation Description. The Installation Description can be saved in the program or in a configuration file. The configuration file is used to move the data entered to a new version of the program or even to a different BARR product or to configure the software for communication with a second host.

Save changes to C:\BARR\BARR3270.EXE file?

Yes Default. Save changes with the .EXE program file.

No Do not save changes in the program file.

Save parameters to a configuration file?

No Default.

Yes Save the changes to the configuration file. When BARR/3270 is loaded, you can call a configuration file which contains the options defined by another version of the program. The character @ followed by the configuration file name tells BARR/3270 to load the configuration file. If the @ character is not followed by a file name, then the default BARR.CFG is used.

Examples:

BARR3270 @BARR.CFG
BARR3270 @OLD.CFG I

If you want the configuration file to become a permanent part of the program, invoke

BARR3270 @OLD.CFG I

to load the configuration file.

Select Exit and Save Changes.

Select Yes to save to the .EXE file.

The configuration parameters will be saved to the BARR3270 program.

Configuration file:

BARR.CFG Default file name. You can supply a different configuration file name.

See Startup Instructions in Chapter 7 for loading the configuration from a file.

Press ENTER to go to the Exit Options screen.

Begin communication at Operation screen

Goes directly to the Operation screen and starts BARR/3270.

Exit to DOS

Return to DOS.

Return to Installation Description

Goes back to the Installation Description screen.

5.12 End of Installation

You have completed the Installation Description.

The following screen from the INSTALL program will notify you of completion.

After you have used the distribution disk (the one we sent you) to create a production disk (or copy on a hard drive), store the distribution disk in a safe place. You should also make a backup copy of your production disk.

Go on to Chapter 7 for startup instructions (unless your application requires the seldom used Tuning Data parameters discussed in Chapter 6).

5.13 Performance Tuning

Several guidelines for maximizing the performance of SNA communications are discussed below.

Choosing a Larger Buffer Size Use a Dlogmode with BUFSIZE=1024.

Transferring Larger Data Frames You can increase throughput by sending larger frames of data. In the VTAM PU Definition, send 1024 bytes by setting MAXDATA=1033. Compared to sending a number of smaller frames, the amount of control information and total number of frames sent are reduced. Under Tuning Data, Additional Parameters, set Memory Allocated for Buffers to 150000. This must  be increased when MAXDATA=1033.

Using Optimal Pacing Parameters Setting pacing parameters to larger values can improve BARR/3270 performance. With PACING=8 and VPACING=8 in the VTAM PU definition, 8 data frames can be sent by the host before a pacing response is required. On a half-duplex line 7 frames are sent at a time. When PACING=8 is used, it is always possible that the pacing response will be returned in time for 7 more frames of data to be sent. The PU should include MAXOUT=7.

Setting Full-Duplex Mode In the VTAM PU Definition, specify DATMODE=FULL. Maximum performance of BARR/3270 can be achieved with full-duplex mode. Full-duplex enables you to send and receive data at the same time, more than doubling throughput. When data is only one-way, either being sent or received, throughput is increased by eliminating delays caused by waiting for your turn to send responses to received data.

Connecting Printers to Parallel Ports If your printers support a parallel interface, attach them to the PC parallel ports. BARR/3270 software requires considerably less work to support the parallel ports LPT1, LPT2, and LPT3 than to support the serial ports COM1 and COM2.