hope@gatech.CSNET (Theodore Hope) (06/06/86)
I am writing some software which will ultimately run on an AT&T 3b5 (sVr2).
Part of this ordeal involves reading a tape written on a Big 'Ol IBM machine;
the tape has variable-length blocks of _up_to_ 6444 bytes.
* I can read it on a Vax (4.2bsd): nc = read (fd, buf, 6444)
* I can't read it on an AT&T 3b20 (sVr2): the mtc documentation (documentation,
what documentation?) specifies that the largest possible read is 6144 bytes.
The abovementioned 3b5 is on the other side of the world, and I'd like to
know if anyone can tell me what the max read on the (raw) tape device is.
Is it 6144 (6k), or 8192?
Thanks in advance.
--
Theodore Hope
School of Information & Computer Science, Georgia Tech, Atlanta GA 30332
CSNet: hope@gatech ARPA: Hope%GATech.CSNet @ CSNet-Relay.ARPA
uucp: ...!{akgua,allegra,amd,hplabs,ihnp4,seismo,ut-sally}!gatech!hopedpb@iwtpu.UUCP (Darryl Baker) (06/10/86)
In article <3794@gatech.CSNET> hope@gatech.CSNET (Theodore Hope) writes: >I am writing some software which will ultimately run on an AT&T 3b5 (sVr2). >Part of this ordeal involves reading a tape written on a Big 'Ol IBM machine; >the tape has variable-length blocks of _up_to_ 6444 bytes. > > * I can read it on a Vax (4.2bsd): nc = read (fd, buf, 6444) > > * I can't read it on an AT&T 3b20 (sVr2): the mtc documentation (documentation, > what documentation?) specifies that the largest possible read is 6144 bytes. > > >The abovementioned 3b5 is on the other side of the world, and I'd like to >know if anyone can tell me what the max read on the (raw) tape device is. >Is it 6144 (6k), or 8192? After a couple of years at the ATT UNIX System Support Center I think I can answer these questions. For the 3b20: The limit is 6k(6144) bytes using a un52 tape controller. The limit is much larger with a TIOP, un132, and Keystone III combination. (This was new when I left and I've forgotten the limit but it was greater than 14k). Yes, Virginia it will read tar tapes blocked at 20). For the 3b5: The limit is 8k(8192) bytes. -- ________________________________________________________________________________ From the sleepy terminal of Darryl Baker ihnp4!laidbak!dpb
djmolny@cuae2.UUCP (DJ Molny) (06/11/86)
In article <3794@gatech.CSNET> hope@gatech.CSNET (Theodore Hope) writes: >The abovementioned 3b5 is on the other side of the world, and I'd like to >know if anyone can tell me what the max read on the (raw) tape device is. >Is it 6144 (6k), or 8192? > >Thanks in advance. >-- >Theodore Hope >School of Information & Computer Science, Georgia Tech, Atlanta GA 30332 >CSNet: hope@gatech ARPA: Hope%GATech.CSNet @ CSNet-Relay.ARPA >uucp: ...!{akgua,allegra,amd,hplabs,ihnp4,seismo,ut-sally}!gatech!hope The maximum tape block size supported on the 3B5 and 3B15 is 8Kb (8192 bytes). The 3B20 has a (relatively) new option that allows it to read and write blocks up to 30Kb. -- Regards, DJ Molny N9609U ihnp4!cuae2!djmolny