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- Newsgroups: comp.sys.ibm.pc.hardware
- Path: sparky!uunet!zaphod.mps.ohio-state.edu!usc!wupost!zazen!schaefer.math.wisc.edu!wilson
- From: wilson@schaefer.math.wisc.edu (Bob Wilson)
- Subject: Re: What's the real difference between QIC-40 and QIC-80?
- Message-ID: <1993Jan11.161122.11527@schaefer.math.wisc.edu>
- Organization: Univ. of Wisconsin Dept. of Mathematics
- References: <1993Jan6.091131.12040@engr.uark.edu> <1993Jan5.134512.710@grebyn.com> <1993Jan7.025054.721@mlb.semi.harris.com> <C8tTrAoHBh107h@dadstoy.gbdata.com>
- Date: Mon, 11 Jan 93 16:11:22 GMT
- Lines: 61
-
- zatar@dadstoy.gbdata.com (Terry Stockdale) writes:
-
- >In <1993Jan7.025054.721@mlb.semi.harris.com> sonny@charybdis.harris-atd.com (Bob Davis) writes:
- >>>richk@grebyn.com (Richard Krehbiel) writes:
- >>>
- >>>>What feature is it that makes the DC2120 tape store 120M on a Jumbo
- >>>>250 and only 60M on a Jumbo 120? Does QIC-80 have twice as many
- >>
- >> Isn't the only difference between the Jumbo 250 and the
- >>Jumbo 120 that the 250 employs on-the-fly data compression algorithms
- >>(sorta like Stacker) to squeeze roughly twice as much data (on the average)
- >>onto the tape as the 120?
- >>
- >> Aren't the on-tape capacities and recording hardware the same?
- >>Just that software (firmware?) has squeezed the redundancy from the
- >>data presented to the 250?
- >>
-
- >I'm sure they both do. I have a Jumbo 120 drive. It gets 60megs on a
- >DC2120 tape without compression and "up to 120megs" with the compression
- >included in the jumbo software. The software for the 120 and 250 are
- >the same. However, I get effective compression on my game drive of
- >about 1.1:1, rather than 2:1, and about 1.4:1 on my other drive. I've
- >never seen anything like a 2:1 average compression out of my drive.
-
- >> Are OS/2 drivers yet available for the Jumbos?
-
- >Nope, and yes. Colorado will sell you Sytos (sp?) software for $99 to
- >support OS/2 2.0. You can find more info on comp.os.os2.misc, where
- >it's discussed rather often. I do not run OS/2 2.0, YET, until I upgrade
- >to a larger hard drive (last weekend, I upgraded a 386sx-16 motherboard
- >to a 486DX-33). The lack of Colorado support for OS/2 was also prominent
- >in my reluctance to convert. I've become a win3.1 user, for lack of tape
- >support.
- >--
-
- >--
- >__
- >"Even if you're on the right track,
- >you'll get run over if you don't move." --Will Rogers.
-
- >terry@dadstoy.gbdata.com Terry Stockdale Houston, Texas
- 2120 only identifies the physical tape. The two different drives
- format it in different ways. The 120 formats it in accordance with the
- QIC40 standard, the 250 as QIC80. QIC 80 has about 50% more tracks and
- about a 50% higher bit density on the track: I don't have the exact
- figures here, but the resulting product doubles the total bits you can
- put on the tape.
- The 250 can READ a QIC40 tape so it is supposed to be able to recover
- from dumps done with a 120: I haven't tried that. It does not format
- QIC40 and I does not claim to be able to write to QIC40 even if
- previously formatted elsewhere.
-
- Thus there is a 2 to 1 difference in the number of bits you can store
- with the 250. The software, or the optional compressing hardware, does
- compression in either case. I have put over 200 MB of "realworld" data
- on a QIC80 formatted 2120 in a Jumbo 250, although the number of bits
- it can store is only about 120MB.
-
- Bob Wilson
- wilson@math.wisc.edu
-