dtb@adpplz.UUCP (Tom Beach) (12/04/90)
There has been a fair amount of discussion here recently over the relative merits of the competing helical scan technologies. What's the opinion of the readership on the future of QIC technology. Using embedded servo track following technology would allow reasonable track densities and these cartridges have far and away higher surface areas than the small helical scan cartridges. There will be 1.3 GB QIC drives available for evaluation within the next 3 months. That matches today's DAT drives with, in my opinion, greater future capacity enhancements than DAT. I'm not sure that QIC isn't being written off too quickly in this forum. Of course, I'm back to the net only recently afer being away for 2 years so you may have covered this recently. If so, my apologies! Tom ------------------------------------------------------------------------ | Tom Beach : Sr Project Engineer : Mass Storage Technology | | phone : (503) 294-1541 | | email : uunet : dtb@adpplz.uucp | | ADP Dealer Services, ADP Plaza, 2525 S.W. 1st Ave, Portland OR, 97201 | ------------------------------------------------------------------------
chris@com50.c2s.mn.org (Chris Johnson) (12/05/90)
In article <363@adphdw20.UUCP> dtb@adpplz.UUCP (Tom Beach) writes: >There has been a fair amount of discussion here recently over the relative >merits of the competing helical scan technologies. > >What's the opinion of the readership on the future of QIC technology. >Using embedded servo track following technology would allow reasonable >track densities and these cartridges have far and away higher surface >areas than the small helical scan cartridges. > >There will be 1.3 GB QIC drives available for evaluation within the >next 3 months. That matches today's DAT drives with, in my opinion, >greater future capacity enhancements than DAT. > >I'm not sure that QIC isn't being written off too quickly in this forum. While it is true that a QIC tape offers far more magnetic tape surface area than either DAT or 8mm, I wonder if the helical scan technologies are not able to make more full use of what area is available. That is, can a linear parallel track recording method use as much as a helical scan recording method given the same area passing under the record heads? I don't think so, but I'm no expert. I'd like to see some comments from some people who might know. Another advantage helical scan technologies have over QIC at the moment, is that 4mm and 8mm tape cartridges are much cheaper. In quantities, QIC tapes are still close to $20 a pop, while we can get 8mm tapes for $3.xx each. The helical scan tapes are also much smaller, physically, allowing smaller form factors in tape drives, and less space required for archived tape storage. Yet another advantage of 4mm and 8mm technologies over QIC is that they are start/stop tape positioning devices versus streaming tape devices. If you've ever watched a QIC tape drive shuffle back and forth, you know what I mean. QIC devices waste a lot of time repositioning the tape. Transfer rates suffer. On the other hand, if someone could provide a 6+ gigabyte QIC tape cartridge with 250 kilobyte per second average data transfer time, and sell the tapes themselves for around $10-12 each, we will buy lots of them. Right now, optical tape looks like an attractive, soon to be available archival media, too, for those who do not need to rewrite their media. If the optical tape media costs can be made low enough, you could essentially never worry about it. -- ...Chris Johnson chris@c2s.mn.org ..uunet!bungia!com50!chris Com Squared Systems, Inc. St. Paul, MN USA +1 612 452 9522
robl@idca.tds.PHILIPS.nl (R. Luursema) (12/07/90)
In article <1990Dec4.194504.28493@com50.c2s.mn.org> chris@com50.c2s.mn.org (Chris Johnson) writes: >... >On the other hand, if someone could provide a 6+ gigabyte QIC tape cartridge >with 250 kilobyte per second average data transfer time, and sell the tapes >... Have you ever calculated how much time it would cost to write that 6Gb? Well, I have; Almost 7 hours! (if you can supply continously 250KBps) We definitly need higher transfer rates, but I doubt that with current days DMA contructions. Rob.
taylor@chris.Solbourne.COM (Dick Taylor) (12/11/90)
In article <1990Dec4.194504.28493@com50.c2s.mn.org> chris@com50.c2s.mn.org (Chris Johnson) writes: >In article <363@adphdw20.UUCP> dtb@adpplz.UUCP (Tom Beach) writes: >>There has been a fair amount of discussion here recently over the relative >>merits of the competing helical scan technologies. >> >>There will be 1.3 GB QIC drives available for evaluation within the >>next 3 months. That matches today's DAT drives with, in my opinion, >>greater future capacity enhancements than DAT. >> >>I'm not sure that QIC isn't being written off too quickly in this forum. > ... > >On the other hand, if someone could provide a 6+ gigabyte QIC tape cartridge >with 250 kilobyte per second average data transfer time, and sell the tapes >themselves for around $10-12 each, we will buy lots of them. > This would make it barely competitive with the 5GB 8mm drive, except for the transfer rate (which is about 500 Kb/s for the 5GB drive, or so I hear). With 5 1/4" disk capacities headed for 2GB in the very near future, and with disk transfer rates already over 3 MB/s and climbing, I don't have a lot of hope for a device whose transfer rate is only 0.25 Mb/s. And a medium cost that's still 2x per megabyte (to be generous) doesn't sound to me like it will be tremendously popular. I'm not writing off QIC immediately -- it seems to me that it's in the same state as 1/2" tape was a few years ago, in that the drives are ubiquitous and this installed base will keep the technology going a while. On the other hand, I don't see a lot of systems with large (> 150 MB) QIC drives in them, and I do see a lot of 8mm drives out there. As far as future tape technology, I'm a little bit of a skeptic about anything except 8mm videotape and RDAT. Between the two of them, I like the 8mm, because it's fast and huge and has been shipping long enough that Exabyte has most of the bugs out. RDAT is a good bet to get really big when the true 3 1/2" RDAT drives are available -- it's the obvious medium for data interchange for really small systems. >-- > ...Chris Johnson chris@c2s.mn.org ..uunet!bungia!com50!chris > Com Squared Systems, Inc. St. Paul, MN USA +1 612 452 9522 -- Dick Taylor Solbourne Computer, Inc.