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From: cdold@starfish.Convergent.COM (Clarence Dold)
Newsgroups: comp.periphs,comp.unix.microport
Subject: Re: tape streamers question
Message-ID: <895@starfish.Convergent.COM>
Date: 20 Dec 88 16:16:37 GMT
References: <1516@bebux.UUCP>
Organization: Convergent Technologies, San Jose, CA
Lines: 40

From article <1516@bebux.UUCP>, by henk@bebux.UUCP (Henk Dijkstra):
> I would like to purchase a tape-streamer however one of my wishes is
> that it is compatible with "frequently" used tape-streamers on UNIX systems.
> From what I hear that means I have to buy a "QIC-24" format compatible

There are a few QIC numbers that you might need to know:

QIC-02: The interface from the CPU or PC-BUS card toward the tape system.

QIC-11: The Data format on a DC300 cartridge, yielding 4 track 20MB.

QIC-24: The Data Format on a DC600A cartridge yielding 9 track 60MB.
	This is the most popular, but really comes in two flavors:
	Big-endian, and little-endian.  For instance, NCR Tower uses
	little endian, and Convergent S/640 uses big-endian, so that 
	dd conv=swap is needed to transport cpio files.

QIC-36: On the earlier decks, there were separate controller and deck logic
	boards.  QIC-36 was the interface between the two, and can generally
	be disregarded, since add-on tape systems won't be divided here.

QIC-120: Data format on a DC600A cartridge yielding 15 tracks 125MB.

QIC-150: Data format on a DC600XTD cartridge yielding 18 tracks 150MB.

In the Archive series of drives, the SCORPION series is available as
20MB, or 60MB.  The 60MB can read 20 MB tapes in the QIC-02 based drives,
but the SCSI interface drive gives up the 20MB ability.  I am not sure
about writing 20 MB on the QIC-02 based version.

The VIPER series will read a 60MB, 120MB or 150MB tape.  The 150MB VIPER
will write 150MB, 18 tracks, if it detects a DC600XTD cartridge; and will
write 125MB, 15 tracks, if it detects a DC600A cartridge.  It cannot write
a 60MB tape.
The tape speed on the 60MB and higher tapes is 90IPS, yielding about 90KB/S
transfer rate, if you can keep the tape streaming, which requires either
double threaded bufferring, or at least very large buffers.
-- 
Clarence A Dold - cdold@starfish.Convergent.COM         (408) 434-2083
                ...pyramid!ctnews!professo!dold         MailStop 18-011
                P.O.Box 6685, San Jose, CA 95150-6685