Nevermind. I was off in my calculation of the CCB address. This is the CCB--and, yes, the residual count looks correct. Thanks.
0030C200 0D000000 00500320 00500328 Sincerely, Dave Clark -- int.ext: 91078 direct: (937) 531-6378 home: (937) 751-3300 Winsupply Group Services 3110 Kettering Boulevard Dayton, Ohio 45439 USA (937) 294-5331 On Mon, Dec 15, 2025 at 1:32 PM David Clark <[email protected]> wrote: > >> The first 16 bytes of the DTF is a CCB. One of the 16-bit fields in > the CCB is the residual count. > > Then I am confused, because it looks like the CCB, in my case, is as > follows after reading the first card. The compile listing also seems to > say that the first two bytes are the residual count. If that is correct, > did I read 80? ...or did I read only 48? This seems reversed. However, > the 7th half-word would be right. > > 00500300 00500340 00066150 00308200 > > > CARDIN DTFCD DEVADDR=SYSRDR,DEVICE=3505,IOAREA1=CARD_IA,BLKSIZE=128, X > ERROPT=IGNORE,EOFADDR=DATAIN > +* IOCS AND DEVICE INDEPENDANT I/O - DTFCD -5686-007-02-C440 @U31TUJS > +* 5686-007 (C) COPYRIGHT IBM CORP. 1981,1989 @U31TUJS > +* LICENSED MATERIAL - PROGRAM PROPERTY OF IBM @D149DBF > + DC 0D'0' > +CARDIN DC X'000082000000' RES. COUNT, COM. BYTES STATUJJ > + DC AL1(0) LOGICAL UNIT CLASS > + DC AL1(0) LOGICAL UNIT > + DC A(IJCX0017) CCW ADDRESS @D33FDVS > + DC 4X'00' CCB-ST BYTE,CSW CCW ADDR. > > Sincerely, > > Dave Clark > -- > int.ext: 91078 > direct: (937) 531-6378 > home: (937) 751-3300 > > Winsupply Group Services > 3110 Kettering Boulevard > Dayton, Ohio 45439 USA > (937) 294-5331 > > > On Mon, Dec 15, 2025 at 12:12 PM Charles Mills <[email protected]> wrote: > >> 50-year-old memory so take this with a grain of salt: The first 16 bytes >> of the DTF is a CCB. One of the 16-bit fields in the CCB is the residual >> count. So if the DTF is expecting 128 bytes and reading 80, the field will >> contain 48 = x'0030'. >> >> But I would think that scanning for binary zeroes or translating them to >> blanks would be a perfectly acceptable approach. >> >> Charles >> >>
