From: BUC@FINABO.ABO.FI (Johan Boholm, DC)
Subject: RE: Problems with CA-ARCHIVER 4.0 and Exabytes
Organization: Abo Akademi University, Finland
Date: Fri, 13 Nov 1992 08:20:44 GMT
X-News-Reader: VMS NEWS 1.24

Brian Tillman, Smiths Industries (tillman@swdev.si.com) writes: 

>> My CA-Archiver V4.0 manuals (the release notes, I think) explicitly state 
>> that 8mm tapes are not supported at this time.  CA told me V4.0 _might_ 
>> work with an 8mm drive, provided the drive supports long EOF records.  
>> The explanation is that, at the end of each archive service run, a copy of 
>> the archive database is placed on the tape (for use by  ARCMAN RECOVER).  
>> At the next service run, this copy of the database is overwritten by the 
>> new files being archived.  In order to properly position the tape, long 
>> EOFs are required.  Otherwise, Archiver can't find the old database file 
>> properly.
>> 

Don Roberts, Beckman Industries, Inc. (dsroberts@beckman.com) writes:

> Not quite correct, Brian.
> 
> From the 4.0 (9111) release notes:
> "Currently CA-ARCHIVER offers support for 8mm tape subsystems that provide
> complete support for Digital Equipment's Tape Mass Storage Control Protocol
> (TMSCP).  Most of the vendors of 8mm based tape subsystems state they are 
> TMSCP compatible, but in most cases they are not 100% compatible.  With the
> current technology provided by EXABYTE, 100% compatibility can only be 
> achieved when the EXABYTE is configured to support the long file markers 
> (2mb).  When the drive is configured to write short file marks (256k), the 
> EXABYTE drive can only begin to write operations at the beginning of the 
> tape or at the end.  In short file mark mode, you can not overwrite 
> information on a 8mm tape, this is not TMSCP compatible.  The EXABYTE drive 
> provides for configuring either way, but not all vendors selling the 
> subsystems support this.  CA-Archiver requires the ability to overwrite 
> data on tape, thus only 8mm subsystems operating in long file mark mode are 
> supported."

> It then states that CMD Technology and MegaTape GT-88/3 do and TD Systems
> Viking SCSI doesn't.  It says that the long file mark must be written after
> each FILE, not just for the archiver database.  "It is quite possible that 
> the file markers will consume more space on a tape than actual data if small
> files are being archived to this medium."
 
> I can't figure out where I put my release notes for 4.1 so I can't verify if
> support is in that version (I'm running 4.1 (9206) but I have no 8mm drives).

Thanks for your comments!

Yes, I have read the 4.0 (9202) release notes and I was (then) glad to
hear that 8 mm tape subsystems are supported _if_ they provide support
for TMSCP.

From the SI8000C series tape subsystem user guide:

"The SI8000C series cartridge tape subsystem includes an 8 mm cartridge
tape drive (an 8200C or 8500C) with SCSI interface that attaches to the
standard tape interface (STI) on a hierarchial storage controller (HSC),
using tape mass storage control protocol (TMSCP)."

The problem *should* be corrected in version 4.1, i.e. 8mm will be
fully supported. I think I'll just grab the phone and start asking
when it will be available here in Finland...


   -------------------------------------------------------------------
   Johan "BUC" Boholm                  e-mail: buc@abo.fi
   Computing Centre                    Phone:  358 + 21-654 379 (work)
   Abo Akademi University,             FINLAND