ward@cfa.harvard.EDU (Steve Ward) (05/26/88)
I am seeking volunteers to assist in porting QIC-40 cartridge tape drives to
a variety of computers and operating systems. Volunteers will write
software to read/write tape cartridges on QIC-40 tape drives that are
fully compliant with the QIC-40 standard. All software will be made available
for unconditional distribution and use.
The type of software to be written will be tape drive utilities supporting the
QIC-40 tape data format, such as user file read/write/delete, directory
read/write/delete, disk backup, etc. Also, device driver support will be
needed. You can basically do what you want, as long as it results in
the ability to read/write QIC-40 compliant tape cartridges on your computer
and operating system. Some discussion in this area is warranted, of course.
I will be able to provide documentation. I will also provide some tape drives
on at least a loaner basis, and possibly arrange donation of the hardware.
The computer tape drive interface may not be provided, but this point is open
for discussion.
This effort is undertaken with the cooperation and support of one tape
drive manufacturer at this point in time. The efforts will be public,
period. The benefits are derived from working on something that benefits
us all. The manufacturer gains by obtaining an expanded market from this
effort, but the effort potentially applies to all QIC-40 tape drives.
I am coordinating this effort without personal compensation, but will
probably gain a few tape drives for use at work and some professional
experience along the way. I hope to gain a viable, operating system-
independent, data tape interchange method, implemented on all the
computers and operating systems used at my work place.
I am also forming an informal mail list for all parties interested in QIC-40
and wanting to know more about QIC-40 and these QIC-40 porting efforts.
Contact me to obtain further information or volunteer. Contact information
is at the end of this message.
The goal is to propagate a low cost (these drives cost $300-$600 retail)
reliable, moderate data capacity (40 MB/tape), small (DC2000 cartridge)
tape cartridge standard to be used for workstation backup and data interchange
between computers of all sizes and costs, but especially workstations. Since
the tape drive fits in a half-height 3 1/2 inch or 5 1/4 inch peripheral
footprint, it is ideal for PC's and workstations. It is ideal as an
inter-operating system exchange format because the QIC-40 standard is a
complete specification which addresses tape labelling and file system/name
description.
Quick QIC-40 Overview
=====================
QIC stands for quarter inch cartridge. QIC standards such as QIC-40 are
issued by a quarter inch cartridge tape drive manufacturer's committee.
These standards are industry standards, not ANSI or ISO, though the QIC
members comprise all quarter inch cartridge tape drive manufacturers, to the
best of my knowledge.
The QIC-40 standard defines a quarter-inch cartridge tape drive electronic
interface, data cartridge physical encoding format, and data cartridge
logical encoding format.
The tape drive electronic interface is based on the common floppy disk drive
interface technology and standards, and alternately, the SCSI interface.
When the SCSI interface is used, it is layered, which is to say that the tape
drive side of the SCSI controller supports the QIC-40 compliant tape drive
interface based on the floppy disk drive interface, as previously stated.
The tape drive electronic interface is a floppy disk drive interface but the
number of "floppy" tracks, sectors/track, and sector size vary from what is
typically encountered on floppy disk formats.
The SCSI interface is the interface of choice since it provides a high level
programming view of the QIC-40 tape drive, translating the physical addressing
of the "floppy" interface into a logical block addressing mechanism. The
SCSI interface to the drive will be the main focus of this effort, but those
who insist on working with a "floppy" interface are also encouraged to
join the effort.
The data cartridge physical encoding format describes the encoding/decoding
algorithms and format necessary to read/write a data bit-stream onto the
data cartridge. The DC2000 data cartridge is used. 40 Megabytes of data
can be stored on a QIC-40 cartridge. A high degree of data redundancy and
use of error check/correct encoding make the drive highly reliable for data
retention, recovery, and tape cartridge interchange among different (including
different vendor QIC-40 drives) tape drives.
The data cartridge logical encoding format describes a standard format for
describing the tape (bad block info, timestamps, etc) and the directory and
file structure of the data (file naming with hierarchical directory info).
IMPORTANT DISTINCTIONS
======================
Many QIC-XX tape drives exist on the market. They can claim viable and
reliable tape drive electronic interfaces and tape cartridge physical
encoding methods. Unfortunately they DO NOT define the data cartridge
logical encoding format. This means that potentially one can interchange
cartridges of the same QIC-XX variety between different vendor tape drives
or between tape drives on different operating systems, but don't hold your
breath.
The operating system and/or user software must deal with the data
cartridge logical encoding format in order to label the tape and data
files, and hopefully include directory information. Without a defined
standard every tape drive vendor and operating system vendor does it
differently, destroying one of the great attractions of quarter-inch
cartridge tape drives: operating system-transparent tape interchange among
tape drives of the same ilk. This only exists on 9-track tape drives
using TAR or ANSI tape labelling.
QIC-40 is a complete standard, including data cartridge logical encoding
format definitions. This means that QIC-40 compliant tapes can be read or
written on any QIC-40 tape drive on any operating system using software
utilities and/or drivers which are also QIC-40 compliant. Since a standard
exists everyone has the same target to shoot at. Most importantly, the
standard deals with file system issues, making it complete enough to allow
operating system transparency through compliance with the standard.
STATE-OF-THE-MARKET
===================
Many vendors are selling QIC-40 tape drives with software (fully QIC-40
compliant) for use on IBM PC's and clones using MSDOS/PCDOS, and this
sums up the market state. What we need is MAINLY (I am not ruling out
PC-oriented volunteers, especially Xenix 286/386) volunteers to work with
DEC VAXstations/MicroVAXes, Sun Microsystems workstations, Apollo work-
stations, AT&T workstations, etc. Let's get QIC-40 up and running under Unix
(use your local flavor) and VMS and whatever else is out there.
PRIME VOLUNTEERS
================
Prime volunteers have or are willing to obtain their own SCSI host adaptor
for their computer and/or their own floppy disk controller. I may be able
to provide a limited number of SCSI host adaptors, but this is shaky at
present. If your interest runs high but you can't swing a SCSI host
adaptor or floppy controller, send in your name, anyway. An attempt will be
made to get you going and in any case, the software effort will be
partitioned into device-independent and device-dependent portions.
SEND ME THE FOLLOWING INFORMATION:
==================================
Please send me your name, phone number, US mail address, e-mail address.
List the computer(s) and operating system(s) with which you are most interested
in using QIC-40 tape drives. Indicate whether you want to join the mailing
list or volunteer software assistance. If you are volunteering for possible
software assistance, then indicate whether you prefer or require to work with
the SCSI interface or the floppy interface.
SEND TO: Steven M. Ward (mail stop 25)
======== Harvard-Smithsonian Observatory
60 Garden Street
Cambridge, MA 02138
(617)495-7201
{ihnp4,seismo}!harvard!cfa!ward
ward@cfa.harvard.EDU