levy@ttrdc.UUCP (Daniel R. Levy) (08/23/88)
In article <301@pvab.UUCP>, robert@pvab.UUCP (Robert Claeson) writes: > In article <4799@netnews.upenn.edu>, spolsky@eniac.seas.upenn.edu (Joel Spolsky) writes: > > You can, however, move 1/4 tapes between a Sun and an AT&T 3Bn. I've > > done that. > How? If you have the 60 MB SCSI drive (such as what the 3B2/600 has builtin, or available as a SCSI accessory for other 3B machines), tapes written on it are readable using /dev/[n]rst8 on a SUN with 0.25" cartridge tape drive and vice versa. The 23 MB 3B2/400 streaming drive isn't compatible with anything on the SUN however. -- |------------Dan Levy------------| THE OPINIONS EXPRESSED HEREIN ARE MINE ONLY | Bell Labs Area 61 (R.I.P., TTY)| AND ARE NOT TO BE IMPUTED TO AT&T. | Skokie, Illinois | |-----Path: att!ttbcad!levy-----|
robert@pvab.UUCP (Robert Claeson) (08/28/88)
In article <2871@ttrdc.UUCP>, levy@ttrdc.UUCP (Daniel R. Levy) writes: > If you have the 60 MB SCSI drive (such as what the 3B2/600 has builtin, or > available as a SCSI accessory for other 3B machines), tapes written on > it are readable using /dev/[n]rst8 on a SUN with 0.25" cartridge tape drive > and vice versa. The 23 MB 3B2/400 streaming drive isn't compatible with > anything on the SUN however. Oh, I tried it with a 3b2/400. Thought the /400 and the /600 were compatible.
rjd@occrsh.ATT.COM (Randy_Davis) (08/30/88)
In article <308@pvab.UUCP> robert@pvab.UUCP (Robert Claeson) writes: >In article <2871@ttrdc.UUCP>, levy@ttrdc.UUCP (Daniel R. Levy) writes: > >> If you have the 60 MB SCSI drive (such as what the 3B2/600 has builtin, or >> available as a SCSI accessory for other 3B machines), tapes written on >> it are readable using /dev/[n]rst8 on a SUN with 0.25" cartridge tape drive >> and vice versa. The 23 MB 3B2/400 streaming drive isn't compatible with >> anything on the SUN however. > >Oh, I tried it with a 3b2/400. Thought the /400 and the /600 were >compatible. What do *you* mean by compatible??? Yes, they *ARE* compatible... A program compiled on a model 400 can be run on a model 600. The floppy interface between the 400 and 600 is identical (well, actually, the circuitry is better on the 600 - but they can both access the same format, etc...). The option cards that can be plugged into a model 400 can be plugged into the 600 (though not all 600 option cards can be put in a 400). In my observations, the model 600 is *backward compatible*, it may even be advertised as such (I do not know - I have never seen an advertisement for one, a big mistake on AT&T's part in my opinion). This means that most everything that runs on a 400 will run on a 600 (within reason - most exceptions are noted as such). This does *NOT* mean that everything that runs on a 600 will run on a 400, or that you can trade hardware between the two without restrictions. There is a large amount of common hardware (peripheral devices, circuit cards, etc...) that are common between the two, but there are more non-common devices than common ones. In this specific case, you are speaking of tape drives. There are three present types of quarter-inch cartridge (QIC) tape drives put into the 3B2 line of computers. The first, the 23 MB drive, is used only in certain model 400s, though the interface card (the 195H circuit module) can be plugged into *any* of the 3B2 computers, though I do not know why anyone would want to do so, with the availability of the SCSI tape and subsystem. The second QIC tape drive is the 60 MB SCSI drive. SCSI, meaning that it interfaces to the SCSI bus, thus requiring a 3B2 SCSI Host Adpater (the 195W, at present) to let the 3B2 talk to it. The 60 MB drive is totally different from the 23 Mb drive - different method of writing data on the tape, format written "on the fly" with the data, inablility to make a file system because it cannot seek, etc... These limitations turn out to be trivial, as the tape is almost always used as a backup device, for archival purposes instead of being used as a filesystem. Some models of the 400 come with the SCSI Host Adapter and the 60 MB SCSI tape drive from the factory. The third type of QIC drive is the 120 MB SCSI drive. It is very similar to the 60 MB SCSI drive, and for that reason, just as different to the 23 MB drive as the 60 MB is. The 120 MB drive can even read the 60 MB tapes, though it will only write in the 120 MB "format". The statement that you "thought the /400 and /600 were compatible" sounds like a contradiction :-). Dan said as much above, "the 23 MB 3B2/400 streaming drive isn't compatible with anything on the Sun however". Does Dan's statement make more sense now? From Dan's statement I infer that the Sun has something that speaks SCSI 60 MB QIC, but nothing that speaks the 23 MB.... Randy Davis UUCP: ...(att!)ocrjd!randy 3B2 System Test Engineering ...(att!)occrsh!rjd AT&T Network Systems, Oklahoma City Works All opinions and/or advice stated above are MY OWN, not those of AT&T.
robert@pvab.UUCP (Robert Claeson) (09/05/88)
In article <337@occrsh.ATT.COM>, rjd@occrsh.ATT.COM (Randy_Davis) writes: > In article <308@pvab.UUCP> robert@pvab.UUCP (Robert Claeson) writes: > >In article <2871@ttrdc.UUCP>, levy@ttrdc.UUCP (Daniel R. Levy) writes: > >> If you have the 60 MB SCSI drive (such as what the 3B2/600 has builtin, or > >> available as a SCSI accessory for other 3B machines), tapes written on > >> it are readable using /dev/[n]rst8 on a SUN with 0.25" cartridge tape drive > >> and vice versa. The 23 MB 3B2/400 streaming drive isn't compatible with > >> anything on the SUN however. > >Oh, I tried it with a 3b2/400. Thought the /400 and the /600 were > >compatible. > What do *you* mean by compatible??? Yes, they *ARE* compatible... With "compatible" I mean that I will be able to run a /400 program on a /600 (which I can) and, for small programs, use a floppy disk or two to move my /400 program to the /600 machine (which I also can) or, for larger programs, use a cartridge tape for the same purpose (which I can't with the built-in tape drive; however, I now know there is an external QIC-24 drive for the /400 machine as I got to know in a message I received a few hours ago and as you points out in your article). Can we please close the subject now?