From: lee@dlpco.COM (Lee Penn)
Newsgroups: biz.sco.general
Subject: Re: Tape backup revisited/CTAR/Tape verify
Date: 25 Jul 92 13:44:23 GMT
Organization: [resent by] The SCOGEN gateway and Propagation Society
Resent-From: mmdf@xenitec.on.ca
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>From uunet.uucp!xenitec.on.ca!news Fri Jul 24 18:08:11 1992
>To: distribution@xenitec.on.ca
>Newsgroups: biz.sco.general
>Path: xenitec!news
>From: "Paul A. Fischer, Sr UNIX Sys Consultant" <openage.com!paul@uunet.UUCP>
>Subject: Re: Tape backup revisited/CTAR/Tape verify
>Submit-To: scogen@xenitec.on.ca
>Organization: [resent by] The SCOGEN gateway and Propagation Society
>Date: Fri, 24 Jul 1992 12:53:39 GMT
>Message-Id:  <9207240853.aa15301@openage.COM>
>Sender: xenitec.on.ca!news@uunet.UUCP

>>>        I agree and an other nice "feature" would be the ability 
>>>to write not only read different capacities on a tape drive.  For 
>>>example the Sankyo 525MB Cartrige tape can read 30,60,150,300,and 
>>>525. But only writes in 525MB mode. It would be nice to have a 
>>>driver that when you write it to a different node, it changes the
>>>size of the backup. This would mean I wouldn't have to have two 
>>>or more tape drives only one.
>>>
>>>        But that will never happpen it makes too much sense....
>>>

>>I would think that both of these abilities have more to do with the
>>firmware of the tape unit than driver.

>>However, I don't have any low-level programming info on any of the
>>tape drives.  

>Maybe someone will come up with a tape drive that has downloadable microcode?  
>This would make firmware very basic, and if you wanted extra capabilities you 
>would just pay for a microcode upgrade.  This would also make upgrading the 
>microcode a piece of cake.  Lots of multiport vendors do things like this now, 
>why not do it for tape drives.

::::  Sankyo and other tapes with 525 Meg capacity CAN write a 
150/250 Meg tape format that can be read in a 150/250 meg tape 
drive.  They cannot write a 60 meg format.

FYI:  the DC6150 and DC6250 cartridges differ only in the amount 
of tape.  The recording format is different from that used for 
the DC6320 and DC6525 cartridges which are also only different by 
the length of the tape.

If you load a DC600A cartridge into a 150 meg tape drive OR a 525 
meg tape drive, you will be able to store about 125 Meg on it.  
It will be written on using the same recording format as used for 
150/250 meg tape cartridges.

IE:  There is upward compatibility between all the QIC 02 tape 
drives from 60 megs up.  

There is downward compatibility from 1 Gig down to 150 meg drives 
in QIC 02.

At least this is my understanding tho I've not specifically 
tested this. Tom Podnar is my main source fo this info and he is 
the first one to explain it to me.

Hope this all helps.

PS:  While this thread exists, what is the experience of folks 
using DAT tapes in being able to write in one drive and read in 
another drive.  Dangers???

================================================================================
Lee Penn,  DLP Technologies, Inc.                     Voice: 513 232-7791
SCO Advanced Product Center                           FAX: (513) 232-7801
7444 Jager Ct.
Cincinnati, OH  45230-4344                           email: lee@dlpco.COM