levy@ttrdc.UUCP (Daniel R. Levy) (11/20/85)
Can somebody who has worked with this or who has the documentation tell me how the CTC cartridge tape for the 3B2 is supposed to be open()'ed and ioctl()'ed and write()'ten to and read() from in order to get it to stream? My depart- ment has gotten a new 3B2/400, and it has a cartridge tape unit. However, at- tempts by mere mortal programs to read and write from /dev/rSA/ctape1 or /dev/SA/ctape1 produce, not streaming, but a slow, bursty, noisy (and undoubtedly very wearing) back-and-forth motion of the tape as the data is transferred. I know that true streaming is possible; ctccpio does it (but has another flaw; it doesn't take to "at" or "batch" jobs because it wants to open /dev/tty for writing--!). Digging through the /usr/include/sys/ct*.h files gives allusions to ioctls (and a special open) for the tape, but apparently nowhere in the voluminous documentation that came with the 3B2 is this described. (The cc, sgs, and esg utilities were installed for us, and we do not have manuals for them yet--is it documented there? termio(7) in the administrator's manual says nothing about how to control this particular "character special device.") It would be nice to have general purpose "streamin" and "streamout" programs to stream reads and writes, respectively, from and to the tape and to interface via stdout and stdin, respectively, with other programs. (Is this even possible? This would sound like an obvious pair of utilities to go with the tape.) Thank you very much for any hints or information, or even telling me where to look. All replies will be personally acknowledged. --Dan Levy-- AT&T Computer Systems Division, Skokie ..!ihnp4!ttrdc!levy