anthony@cit-vax.Caltech.Edu (Lawrence Anthony) (11/13/89)
a brief news item in the current issue of DEC Professional (Vol 8, No 12 (Nov 1989) p 18) claims that DEC has plans to offer "a 4mm solution" for backup devices. does anybody have any news/rumors on the recording format that DEC will employ (HP/Sony, Gigatrend, or some proprietary DEC format) and when such a device would be available? lawrence anthony anthony@csvax.caltech.edu (818) 356-4474
scs@itivax.iti.org (Steve Simmons) (11/14/89)
anthony@cit-vax.Caltech.Edu (Lawrence Anthony) writes: >a brief news item in the current issue of DEC Professional >(Vol 8, No 12 (Nov 1989) p 18) claims that DEC has plans >to offer "a 4mm solution" for backup devices. does anybody >have any news/rumors on the recording format that DEC will >employ (HP/Sony, Gigatrend, or some proprietary DEC format) >and when such a device would be available? I dunno about rumors, but it really honks me off that DEC will not pursue 8mm technology. There are very few disks in the world that one cannot back up on a single 8mm tape, while even Dec (;-)) has drives too large for a 4mm. Exabyte is announcing a larger capacity second-generation drive as we speak, while 4mm is brand-new technology. Most of our cost of backups is operator time. 4mm buys us nothing, flat, zippo. Feh. Disclaimer: My opinions reflect the Industrial Technology Institute only to the extent to which it follows my opinions. -- Steve Simmons scs@iti.org Industrial Technology Institute You're not a big name on Usenet until someone puts you in their .sig file.
grunwald@foobar.colorado.edu (Dirk Grunwald) (11/14/89)
from my understanding, the advantage of 4mm DAT drives is faster and more precise seeking. Allegedly, you can use one like an old DECtape, and read/write explicit blocks. allegedly 8mm drives, like exebyte, have startup/stopdown times that make fore more difficult block-by-block operation. I don't know how much of this is BS from bad trade rags, but it's what I heard. Dirk Grunwald -- Univ. of Colorado at Boulder (grunwald@foobar.colorado.edu)
tihor@acf4.NYU.EDU (Stephen Tihor) (11/14/89)
I talk to the product managers at DECUS and the DEC line is that the 8mm tapes suffer too many errors and can not be used in a seek and access mode like magnetic tapes. Specifically they do not have good error behavoir if you streat them like normal tapes write files then EOF and EOV and tape marks then backspacing to the EOV and rewriting it with the next HDR label, etc.
burzio@mmlai.UUCP (Tony Burzio) (11/15/89)
In article <4413@itivax.iti.org>, scs@itivax.iti.org (Steve Simmons) writes: > pursue 8mm technology. There are very few disks in the world that > one cannot back up on a single 8mm tape, while even Dec (;-)) has > drives too large for a 4mm. Exabyte is announcing a larger capacity > second-generation drive as we speak, while 4mm is brand-new technology. > Most of our cost of backups is operator time. 4mm buys us nothing, > flat, zippo. Feh. I don't know about you, but our 8mm drive doesn't last long between repairs. In any event, the 4mm drives will eventually store much larger amounts of data. You can also look for autochanger units so 4 or more tapes can be strung together in one backup. There must be some reason why the major vendors (DEC HP etc) are backing the 4mm tapes, but of course they won't say till they have one of their own to sell :-) ********************************************************************* Tony Burzio * Brrr... Getting cold. Martin Marietta Labs * mmlai!burzio@uunet.uu.net * *********************************************************************
mcconnel@b11.ingr.com (Guy McConnell) (11/17/89)
In article <13310019@acf4.NYU.EDU>, tihor@acf4.NYU.EDU (Stephen Tihor) writes: > I talk to the product managers at DECUS and the DEC line is that the > 8mm tapes suffer too many errors and can not be used in a seek and > access mode like magnetic tapes. Specifically they do not have good > error behavoir if you streat them like normal tapes write files then > EOF and EOV and tape marks then backspacing to the EOV and rewriting it > with the next HDR label, etc. That is just DEC's line. The error correction code in the 8mm drive is very sophisticated and quite good. They can do file skips and record skips at 10 times the R/W speed as well. Specifically, the problem with using them on a DEC system is the extreme inefficiency of the TMSCP protocol period, which is amplified when using a helical scan device. You'll find much the same thing on the 4mm products. The good news is that, if they bless the 4mm devices, they'll have to do something to increase driver efficiency and this will benefit the 8mm drives as well. Guy D. McConnell