amartin@wpi.WPI.EDU (Allen R Martin) (06/12/91)
Will Cross-Dos work with an AE high density drive to read IBM high density disks? I don't see any reason why it shouldn't but I was just wondering if anyone has had any experience with this. Allen Martin amartin@wpi.wpi.edu
civir1070@ucsvax.sdsu.edu (FURRY R) (06/12/91)
In article <1991Jun11.215637.563@wpi.WPI.EDU>, amartin@wpi.WPI.EDU (Allen R Martin) writes... > > Will Cross-Dos work with an AE high density drive to read IBM >high density disks? I don't see any reason why it shouldn't but I was >just wondering if anyone has had any experience with this. > > Allen Martin > amartin@wpi.wpi.edu No. Consultron (CrossDos) syss that it will not work. The AE drive will read standart, 720k disks, just like an Amiga drive, but it won't read the 1.44 meg IBM. Consultron said it was because of the way they get 1.52 megs on a floppy was "signifigantly" different from the way big blue does it. Hmmm. I really wish I could use 1.44 megs disks. ___________________________________________________________________ / |CIVIR1070@ucsvax.sdsu.edu| Q: Is there a UNIX FORTRAN optomizer? \ \ | Scott Ellis | A: Yeah, "rm *.f" _ / / |_________________________| _ // Amiga \ \_______________________________________________\X/_________________/
cazabon@hercules (Charles Cazabon (186-003-526)) (06/12/91)
In article <1991Jun12.001931.3711@ucselx.sdsu.edu> civir1070@ucsvax.sdsu.edu writes:
:In article <1991Jun11.215637.563@wpi.WPI.EDU>, amartin@wpi.WPI.EDU (Allen R Martin) writes...
:>
:> Will Cross-Dos work with an AE high density drive to read IBM
:>high density disks? I don't see any reason why it shouldn't but I was
:>just wondering if anyone has had any experience with this.
:>
:> Allen Martin
:> amartin@wpi.wpi.edu
:
:No. Consultron (CrossDos) syss that it will not work. The AE drive will
:read standart, 720k disks, just like an Amiga drive, but it won't read
:the 1.44 meg IBM. Consultron said it was because of the way they get 1.52
:megs on a floppy was "signifigantly" different from the way big blue does
:it. Hmmm. I really wish I could use 1.44 megs disks.
:
Applied Engineering boobed when they desgined their high density drive.
The way an IBM gets 1.44 megs onto a 3.5 inch disk is to slow it down to
half the speed of a 720 K disk (rotational speed, not transfer speed).
That way, they get 18 sectors per track instead of 9, and voila, twice the
storage.
The Amiga puts 11 sectors per track on a 720K disk instead of 9, but it can
read 9 sector per track formats.
To read 1.44 disks, you would need to slow our drives to half their speed,
and then squeeze 22 Amiga sectors on each track, to enable you to read
IBM 18 sector per track format.
Applied Engineering got unreliable reads at that speed, so they didn't slow
it quite that much, and only got 19 secotors per track. Hence, 1.52 megs
per disks. However, also, it will not read the 1.44 disks because of the
difference in speed.
Commodore's high density drive (standard equipment on the 3000UX) manages
to get the reliable reads at that speed, and so can read 1.44 IBM disks,
and also, as a bonus, you get the AmigaDos 1.76 megs/disk format.
AE knew that CBM had to provide 1.44 disk compatibility to comply with
UNIX SVR4 standards; they should have provided for it.
--Chuck Cazabon, cazabon@hercules.cc.uregina.ca
* My Opinions Are Not My Own...Feel Free To Plagiarize easton@zds-oem.zds.com (Jeff Easton) (06/12/91)
In article <507@regina.uregina.ca> cazabon@hercules.uregina.ca (Charles Cazabon (186-003-526)) writes: >Applied Engineering boobed when they desgined their high density drive. >The way an IBM gets 1.44 megs onto a 3.5 inch disk is to slow it down to ^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^ >half the speed of a 720 K disk (rotational speed, not transfer speed). ^^^^^^^^^^^^^^^^ >That way, they get 18 sectors per track instead of 9, and voila, twice the >storage. Er, The IBM style 1.44 Mb disks have the same rotational speed as 720K drives. The data transfer rate was doubled to obtain HD. The same is true of the new 2.88 Mb drives as well. The transfer rate was doubled again. >The Amiga puts 11 sectors per track on a 720K disk instead of 9, but it can >read 9 sector per track formats. > >To read 1.44 disks, you would need to slow our drives to half their speed, >and then squeeze 22 Amiga sectors on each track, to enable you to read >IBM 18 sector per track format. Correct. See below. >Applied Engineering got unreliable reads at that speed, so they didn't slow >it quite that much, and only got 19 secotors per track. Hence, 1.52 megs >per disks. However, also, it will not read the 1.44 disks because of the >difference in speed. If I recall the previous discussions correctly, the Amiga cannot directly connect a IBM 1.44 Mb drive (and use the 1.44Mb storage) because the custom chips are fixed at a data transfer rate of 250 kbits/sec. HD transfers at 500 kbits/sec (thus the halving of rotational speed for the Amiga drive) and ED is 1 Mbit/sec. The downside to all this is that the Commodore version of a 1.44 Mb drive will read/write the HD disk twice as slow as a true IBM can. This assumes that everything but the transfer rate is the same, which I'm sure isnt the case :-). >Commodore's high density drive (standard equipment on the 3000UX) manages >to get the reliable reads at that speed, and so can read 1.44 IBM disks, >and also, as a bonus, you get the AmigaDos 1.76 megs/disk format. Is this shipping now in the UX? If so, where can I get one for my regular old A3000? Is there any Amiga DOS drivers needed to support it? >--Chuck Cazabon, cazabon@hercules.cc.uregina.ca Jeff Easton Zenith Data Systems // Systems Engineer \X/ easton%zds-oem@caspian.cs.andrews.edu easton@andrews.edu What? Preemptive Multitasking in only 256K of RAM? :^) :^) Disclaimer: I dont work in Drive Evaluation. :-)
drysdale@cbmvax.commodore.com (Scott Drysdale) (06/13/91)
In article <507@regina.uregina.ca> cazabon@hercules.uregina.ca (Charles Cazabon (186-003-526)) writes: >In article <1991Jun12.001931.3711@ucselx.sdsu.edu> civir1070@ucsvax.sdsu.edu writes: >:In article <1991Jun11.215637.563@wpi.WPI.EDU>, amartin@wpi.WPI.EDU (Allen R Martin) writes... >:> >:> Will Cross-Dos work with an AE high density drive to read IBM >:>high density disks? I don't see any reason why it shouldn't but I was >:>just wondering if anyone has had any experience with this. >:> >:> Allen Martin >:> amartin@wpi.wpi.edu >: >:No. Consultron (CrossDos) syss that it will not work. The AE drive will >:read standart, 720k disks, just like an Amiga drive, but it won't read >:the 1.44 meg IBM. Consultron said it was because of the way they get 1.52 >:megs on a floppy was "signifigantly" different from the way big blue does >:it. Hmmm. I really wish I could use 1.44 megs disks. >: >Applied Engineering boobed when they desgined their high density drive. >The way an IBM gets 1.44 megs onto a 3.5 inch disk is to slow it down to >half the speed of a 720 K disk (rotational speed, not transfer speed). >That way, they get 18 sectors per track instead of 9, and voila, twice the >storage. um, that's incorrect. the way ibm systems get 1.44 megs on a 3.5" disk is to double the data rate to the drive. of course, the magnetic media has to be able to handle it, and the drive's read/write electronics have to be able to handle it. >The Amiga puts 11 sectors per track on a 720K disk instead of 9, but it can >read 9 sector per track formats. the amiga puts one big "sector" on the disk - there are no sector marks that the hardware searches for. the amiga does not do partial track reads or writes - it does only whole tracks. elimination of the sector marks and headers is where the amiga's disk format gains storage. >To read 1.44 disks, you would need to slow our drives to half their speed, >and then squeeze 22 Amiga sectors on each track, to enable you to read >IBM 18 sector per track format. > >Applied Engineering got unreliable reads at that speed, so they didn't slow >it quite that much, and only got 19 secotors per track. Hence, 1.52 megs >per disks. However, also, it will not read the 1.44 disks because of the >difference in speed. > >Commodore's high density drive (standard equipment on the 3000UX) manages >to get the reliable reads at that speed, and so can read 1.44 IBM disks, >and also, as a bonus, you get the AmigaDos 1.76 megs/disk format. > >AE knew that CBM had to provide 1.44 disk compatibility to comply with >UNIX SVR4 standards; they should have provided for it. > > >--Chuck Cazabon, cazabon@hercules.cc.uregina.ca >* My Opinions Are Not My Own...Feel Free To Plagiarize --Scotty -- =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Scott Drysdale Software Engineer Commodore Amiga Inc. UUCP {allegra|burdvax|rutgers|ihnp4}!cbmvax!drysdale PHONE - yes. "Have you hugged your hog today?" =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
cazabon@hercules (Charles Cazabon (186-003-526)) (06/13/91)
In article <1991Jun12.123802.14255@zds-oem.zds.com> easton@zds-oem.zds.com (Jeff Easton) writes: :In article <507@regina.uregina.ca> cazabon@hercules.uregina.ca (Charles Cazabon (186-003-526)) writes: : :>Applied Engineering boobed when they desgined their high density drive. :>The way an IBM gets 1.44 megs onto a 3.5 inch disk is to slow it down to : ^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^ :>half the speed of a 720 K disk (rotational speed, not transfer speed). : ^^^^^^^^^^^^^^^^ :>That way, they get 18 sectors per track instead of 9, and voila, twice the :>storage. : : Er, The IBM style 1.44 Mb disks have the same rotational speed as :720K drives. The data transfer rate was doubled to obtain HD. The same :is true of the new 2.88 Mb drives as well. The transfer rate was doubled :again. Thanks for the correction--I think I must have been thinking of the way that a friend of mine hooked one up to his Amy...he cut it's speed in half. : The downside to all this is that the Commodore version of a 1.44 Mb :drive will read/write the HD disk twice as slow as a true IBM can. This :assumes that everything but the transfer rate is the same, which I'm :sure isnt the case :-). : :>Commodore's high density drive (standard equipment on the 3000UX) manages :>to get the reliable reads at that speed, and so can read 1.44 IBM disks, :>and also, as a bonus, you get the AmigaDos 1.76 megs/disk format. : : Is this shipping now in the UX? If so, where can I get one for my :regular old A3000? Is there any Amiga DOS drivers needed to support it? Yes, this drive ships as standard equipment now in 3000UXes. I don't know if it did in the first few, but at the Amiga Expo in Calgary, Canada on May 5, I was told that the 3000UX was currently shipping with the new high density drive. However, he was not allowed to tell us whether Commodore had designed a new Gary chip capable of hadling 500 kbits/second, and so I cannot answer that. The new drive is not available for older Amigas in Canada yet (officially) but I can't speak for the US. We frequently get new products faster than the US, sort of like a test market. It has its advantages; but also its disadvantages (i.e....the SideCar). Also, the new C= high-resolution three-button mouse ships with the 3000UX now. Nice mouse, feels good, looks funky. : Jeff Easton Zenith Data Systems : // Systems Engineer : \X/ easton%zds-oem@caspian.cs.andrews.edu : easton@andrews.edu : What? Preemptive Multitasking in only 256K of RAM? :^) :^) : : Disclaimer: I dont work in Drive Evaluation. :-) Neither do I...oh yes, sorry, I do. I guess I don't have an excuse! --Chuck Cazabon, cazabon@hercules.cc.uregina.ca * My Opinions Are Not My Own...Feel Free To Plagiarize