hutch@fps.com (Jim Hutchison) (08/14/90)
Start/stop tape drives seem to be vanishing from the market place. I am
looking for one (in quantity) which goes atleast 75ips at 6250bpi (GCR).
Pertec or SCSI interfaces are acceptable to the general computing product this
would be a part of.
Our desire for start/stop drives relates to a general mix of applications.
Some smart applications can stream tape easily, even at 200ips, but most
applications do not think about tape so expertly.
I've seen such a drive from Telex (75ips, 6250bpi), but it seems to behave
strangely on the Datalink STK interface it connects to.
--
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Jim Hutchison {dcdwest,ucbvax}!ucsd!fps!hutch
Disclaimer: I am not an official spokesman for FPS computingbuck@siswat.UUCP (A. Lester Buck) (08/15/90)
In article <10780@celit.fps.com>, hutch@fps.com (Jim Hutchison) writes: > Start/stop tape drives seem to be vanishing from the market place. And for good reason, since they are becoming quite uneconomic. Imagine the cost for a mechanism that can be moving the tape at 200 ips and then stop it _and_ start it again, all within the .3in interrecord gap at 6250 bpi. These cost tens of thousands of dollars, and they break down a lot. Now consider putting your money in an intelligent cache of several megabytes ($70/MB) and using a much cheaper and simpler streaming mechanism. Assuming you have enough cache on board, you can simulate start/stop behaviour _exactly_ while saving a huge amount of money. Even IBM's top of the line 3480 drive, transferring at a constant 3 MB/sec, is basically a streaming tape drive, although a very high performance version. And all the latest tape developments are coming in helical scan technology, which is much more a streaming technology than start/stop. Helical scan is based on a high head to medium relative velocity, which means the tape has to be "streaming" before any data can be written. -- A. Lester Buck buck@siswat.lonestar.org ...!uhnix1!moray!siswat!buck