SCSItape is a
BeOS
driver for SCSI-2 sequential-access devices, with emphasis on UNIX
compatibility. What does that mean?
- BeOS
Driver
- The driver was written for the
BeOS,
from scratch. Although several tape drivers already existed
at the time of writing, none of them did exactly what I wanted
(in particular, none worked with my DDS-2 drive ;-).
So I wrote another one.
- SCSI-2
- The driver assumes that it will handle devices which comply with the
SCSI-2 standard. No effort was spent to ensure that it would be usable
with older drives.
- Sequential Access
- The SCSI-2 standard lumps tape drives under the general heading
"sequential-access devices." The main difference between these and
disks is that it takes a long time to access widely separated parts
of a tape, and so they are usually read and/or written in a sequential
fashion. The SCSItape driver doesn't directly support any other
kind of use (although it provides positioning commands).
- UNIX Compatibility
- The behavior of the driver was modeled on several UNIX (or UNIX-like)
systems, in particular HP-UX and FreeBSD/OpenBSD.
The driver documentation has been split into several parts:
- The section on Tape Basics contains
an introduction to using tapes, and to their little peculiarities.
- The User's Manual describes how to use
the driver in conjunction with existing programs.
It also documents the tape control program,
mt .
- The Programmer's Manual documents the
behavior of the driver's exported functions, in sickening detail.
- The Glossary explains some tape-related
terms and abbreviations used in this manual.
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I took many ideas for SCSItape (but no actual code) from freely
available sources (for FreeBSD, Linux, and Mach). Thanks to the numerous
authors of these packages for making them available; we think alike.
Trey Boudreau from Be, Inc. gave me some hints for making the device
configuration information persistent.
Geoffrey Clements, Neal P. Murphy and Juan Casero volunteered to test
the driver and deserve some applause for their courage.
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