Apr ill, 1981 CKS/DOS does not support the ASCII, BUFOFF, READ=BACK operands of the DTFKT macro. Tape I/O to reading in the forward direction. HDRINFO, LENCHK, and
operations are limited eMS/DOS creates unlabeled taoes and
User-written label processing routines are
handles tape labels as follows: bypasses standard labels.
used, when supplied. CMS/DOS If
Input tape has
label
Input tape has a
stan dar d label
Input tape has
nonstandard
label
Tape opened for
output The CMS/DOS open routine positions the tape at the
first data record.
The CMS/DOS open routine positions the tape at the
first data record (that is, standard labels are
bypassed). If user labels are detected and if a
user label routine is specified (LABADDR=xxxxxxxx)
in the DTF table for the file, CMS/DOS exits to the
user's routines to read and process the user labels.
The eMS/DOS open routine exits to the user's routine
specified by the LABADDR=xxxxxxxx operand of the DTFKT macro. If no user routine is specified, the
tape is positioned at the first data record. CMS/DOS treats all tapes (standard labeled tapes,
nonstandard labeled tapes, and unlabeled tapes) as
if they were unlabeled. If a tape with a standard
or nonstandard label is opened for output, CKS/DOS writes over the label. This is also true for tape
workfiles because they are opened for output first.
The CKS/DOS close routine does not perform trailer label checking on
input files. No trailer label processing is provided for input or
output tape files.
Figure 38 describes the DTFMT macro operands and their support under CMS/DOS. An asterisk (*) in the status column indicates that CMS/DOS support differs from DOS/VS support.
298 IBM VM/370 System Programmer's Guide

Operand ! IBLKSIZE=nnnnn 1 IStatusl ILength of , 3-2,767) ..
Description
one I/O area in bytes (maximum =
1------------------------------------------------------------------- iDEVADDR=SYSxxx I I I EOFADDR=XXXXXXxx ... _'L._'':_ unit .... ...... _"'- drive I.:JI IU J.JV.1..1.\.., .L VJ.. l..Qt'--= I.l;:>cu I file .. IName of your end-of-file routine .. .... ... ".;,.. J..VJ.. l..u .... .:l 1------------------------------------------------------------------- IFILABL=XXXX 1 I 1 * I (NO, STD, or NSTD).. If NSTD specified, I include LABADDR. User label routines are I supported only for header labels on input I tapes. 1------------------------------------------------------------------- I IOAREA1=xxxxxxxx !Name of first I/O area ..
i I ASCII=YES *
INot supported.
1------------------------------------------------------------------- IBUFOFF=nn I ICKPTREC=YES 1 I ERREXT=YES ERROPT=xxxxxxxx HDRINFO=YES IOAREA2=xxxxxXXX IOREG= (nn) 1 ILABADDR=xxxxxxxx I I 1 I *
*
*
INot supported. ICheckpoint records are interspersed with I input data records. IOCS bypasses I checkpoint records.
IAdditional errors and ERET are desired.
; (IGNORE, SKIP, or name of error routine). I Prevents job termination on error records. INot supported. IIf two I/O areas are used, the name of the I second area.
IRegister number. Use only if GET or PUT I does not specify a work area or if two I/O I areas are used. Omit WORK!.. General I registers 2 through 12, enclosed in I parentheses. IName of your label routine if FIL!BL=NSTD, ! or if FILABL=STD and user-standard labels I are processed. User label routines I are supported only for header labels on I input tapes. 1--------------------------------------------------------------------- ILENCHK=YES * INot supported.
1------------------------------------------------,--------------------- I MODNAME=xxxxxxxx I NOTEPNT=xxxxxx RDONLY=YES READ=xxxxxxx
* IName of MTMOD logic module for this DTF .. If
J omitted, IOCS generates standard name. I (YES or POINTS). YES if NOTE, POINTW, I POINTR, or POINTS macro used.. POINTS if I only POINTS macro used ..
IGenerate read-only module. Requires a
J module save area for each routine using
1 the mod ule .. ICMS/DOS only supports READ=FCRWARD ..
Figure 38. CMS/DOS Support of DTFMT Macro (Part 1 of 2) Part 3. Conversational Monitor System (CMS) 299