On Mon, 24 Jul 1995 18:21:17 -0500 David Boyes said:
>This may be pertinent to the disaster recovery discussion. note
>that the 3590s are not platform specific.
>
>> Reliability
>> * 8mm - quoted at 500 passes but actual reliability is more on the
>>   average of 5-10 passes before failure.
What is meant by a "pass" here?  If you are talking about the same part of
the tape passing over the tape head, then this number is way low.  I think
I've heard numbers like 500 mentioned more frequently.  We replace tapes
after 300 tape mounts (as counted by ADSM).

>> * 3490/3590 tape - quoted at 5,000 full passes, 80,000 short passes..
>>   but actual customer experience is more like 100,000 passes.
Again, I'd like to know if this is the same definition of "pass" that was
used for 8mm or not.  Is there much experience with 3590 tape to know
what a reasonable number of "passes" is?

>> Performance
>> * 8mm - 300-500 KB/sec
>> * 3590 - 9MB/sec
>> In addition, 3590 has quick search capabilities which leave 8mm in
>> the dust.
Agreed.

>> Capacity
>> * 8mm - 5GB
>> * 3590 - 10GB uncompressed (20-30GB compressed)
Yes, but Exabyte now has 7GB tapes (uncompressed), and I (still) hear that
their new "Mammoth" drives are due out soon.  I've heard that for over a
year now, so I don't put much stock in it.  I believe they will hold 20GB
uncompressed, but I don't know that xfer rate.

>> Price - I'm not a marketing guy but one customer told me he
>> pays twice for 8mm cartridges what he does for 3490 cartridges.
>> I don't know the exact cost of the 3590 cartridges but I believe they
>> are on the same order as 8mm cartridge costs.
>>
>> What 8mm does have going for it are that the 8mm drives and
>> libraries have a lower entry cost and are more prevalent.
The price of the cartridges are insignificant compared to the cost of the
tape drive, and the robotics.  I think list price for a 3590 is somewheres
around $45,000 per drive, whereas you can get 8mm drives for less than $4,000.
The robotics are also less expensive for 8mm.  I feel that 3590 will scale
much better than 4/8mm, but the entry costs for 3590 create a barrier for
sites just getting into ADSM (in my opinion).

>>
>> Greg Tevis
>>

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