dkchen@uicsrd.csrd.uiuc.edu (09/13/89)
Hi! I am planning to buy an EXTERNAL 3.5" 1.44MB floppy drive and its controller for my turbo XT clone. Can anybody give me some idea where to start? Thanks. D. Chen
MGREENE@AUVM.BITNET (Michael A. Greene) (09/16/89)
You can't run a 1.44 mb 3.5" from an XT. The data xfer rate is too slow. You can run a 720. Save your money.
davis@clocs.cs.unc.edu (Mark Davis) (09/19/89)
In article <89258.220000MGREENE@AUVM.BITNET> MGREENE@AUVM.BITNET (Michael A. Greene) writes: >You can't run a 1.44 mb 3.5" from an XT. The data xfer rate is too >slow. You can run a 720. > >Save your money. Just to clarify a couple of issues: 1. An XT controller will not handle an 1.44 MB 3.5" drive. Transfer rate limitations do come into effect here. 2. Lots of people (including me) have these drives (1.44 MB) in XT's or clones. All that is involved is replacing the controller. Since the original poster wants an external drive, either Compaticard I or WD-FOX-4 would work fine. The cost of the controller (about $120) would be much less than the cost of the drive in an external case ($150 to $200). 3. The XT bus/motherboard can handle the data transfer rate of the 1.44 drives very well. (Some people with AT's have poor performance, though. Isn't that interesting?) 4. It is true that most PC/XT's will take a 720K 3.5" as a second (B:) drive without other hardware modifications. There are lots of good reasons to consider this route: a. You don't have to buy a new controller b. 720K drives are (a little, like $10) cheaper c. 720K disks are a lot cheaper ($1 vs $4) d. The 720K disks are more standard. Software (like DOS, MS Word, ...) is distributed on them. 1.44 drives can write them without problems, etc, etc. e. Older DOS supports them (3.2) so drivers are less likely to be needed. (I have seen places charging $15 for a driver!) One of the big reasons, cost of HD disks, has recently diminished since disks are now down to about $2.00 each in large quantities mail order. Our campus book store sell 10 3M HD disks for 33.50. Of course, the DSDD disk are $13.50, so the price per megabyte is still lower for the 720K disks. All prices refer to mail order (except where noted). You local store may be higher. I hope this makes things more clear. Thanks - Mark (davis@cs.unc.edu or uunet!mcnc!davis)
smith@ug.cs.dal.ca (Your Worst Nightmare) (09/19/89)
In article <89258.220000MGREENE@AUVM.BITNET> MGREENE@AUVM.BITNET (Michael A. Greene) writes: >You can't run a 1.44 mb 3.5" from an XT. The data xfer rate is too >slow. You can run a 720. > >Save your money. Actually, you can. I've used the Sysgen Omnibridge on a PC clone (not XT, PC) with mixed results. It can be done, but only with a LOT of fiddling. Sean -- /--------------------------------------------------------------------------\ | Sean Smith - Damage Inc. "Let me tell you what you're trying | | Halifax, Nova Scotia, Canada to say..." 01SSMITH@AC.DAL.CA too | | These ideas are mine...ALL MINE!!! *maniacal laughter* |
davem@hpmwtd.HP.COM (Dave McQuate) (09/19/89)
Try a "MegaMate" external 1.44M floppy for PC/XT/AT from MicroSolutions 132 W. Lincoln Hwy DeKalb, IL 60115 (815) 756-3411 It handles 720K/1.4M automatically sensing which. $349 list. I've used 'em on both an XT and AT clones. It has its own floppy controller. Doesn't work with PCTOOLS PCBACKUP because that program doesn't know about the added floppy controller--and it wants to use DMA. But otherwise it's a solid unit. I've had no problems at all. (Disclaimer: I am a dealer for MicroSolutions) Dave McQuate Voice: (707) 577-4585 ARPANET: davem%hpmwtd@hplabs.HP.COM INTERNET: davem%hpmwtd@hplabs.hp.com UUCP: ...hplabs!hpmwtd!davem
waldman2@husc8.HARVARD.EDU (Bruce Waldman) (09/19/89)
Michael Green says...
*You can't run a 1.44 mb 3.5" from an XT. The data xfer rate is too
slow. You can run a 720.*
This is nonsense! I've been running a 1.44 mb 3.5" external drive on
my XT for 6 months (with DOS 3.2). Megamate, sold by Blue Heron, DeKalb
Illinois, fits the bill, comes with driver and software. No problem at
all.
Bruce Waldman, bw@harvarda.bitnet
waldman2@husc4.harvard.edukv56962@tut.fi (V{{r{nen Kari) (09/23/89)
In article <910014@hpmwdjm.HP.COM> davem@hpmwtd.HP.COM (Dave McQuate) writes: > Doesn't work with PCTOOLS PCBACKUP because that program > doesn't know about the added floppy controller--and it wants to use > DMA. I bought a TMC floppy controller a week ago. It can have 4 floppy disk drives, one of which can be external. I am using it on my XT-clone with success. I now have 360 kB as A and 1.44 MB as B. Both drives are internal. PC-BACKUP works fine with my 1.44 MB disk drive. DOS format takes 1 min 26 secs (is that fast or what?)! I don't need drivers of any kind, neither do I need any 'drivparms'. I haven't tested yet, if my XT can boot from that 1.44 MB (changing it to A would be necessary, of course). The controller has a bios of its own. The BIOS of my XT is DTK ERSO BIOS, dated 1986... Now the important point: money. The 1.44 drive is TEAC (check the price yourself). The controller costs about USD 100. However, I had to buy new multi I/O card because the old one was a "multi I/O card with a floppy controller"... Well, to me it was worth it... -- SO LONG AND THANKS FOR ALL THE FISH (The dolphins) Kari Vaaranen Tampere University of Technology Majakkakatu 30, kv56962@tut.fi SF-33410 Tampere, FINLAND
blitter@ele.tue.nl (Blitter_stagairs_Frans) (10/03/89)
OK, now for the total sum up: Standard XT (PC) floppy controllers support only 1 transferrate: 250 kbit/s (Yes, I know they also support 125 kbit/s single density format but this died long ago) With this transfer rate two types of floppys are supported: 360 kb 5.25" and 720 kb 3.5". Also 720kb 5.25" is supported but this never made it in the PC world. Standard AT floppy controllers support 3 transfer rates: 250 kbit/s for 5.25" 360kb and 3.5: 720kb (same as XT) 300 kbit/s for 360kb floppy in 1.2 MB drive 500 kbit/s for 1.2 MB 5.25" and 1.44 MB 3.5" Now the question arises why there is only 1.2 MB on a 5.25" floppy and 1.44 MB on a 3.5" floppy. This is because 1.2MB drives have 360rpm motors and 1.44MB drives turn 300 rpm. All drives except 1.2 MB turn at 300 rpm. This results in 15 sectors/track on a 1.2MB drive and 18 sectors/track on a 1.44MB drive. Now it also becomes clear why you need the 300kbit/s transfer rate in an AT. The normal 360kb floppy in an 1.2MB drive turns at 360 rpm, this means that the you must multiply the standard 250 kbit/s transfer rate with a factor 360/300 and then you get exactly 300 kbit/s. To make matters even more complicated there are certain 1.2MB drives that change speed from 360 rpm to 300 rpm if they are set to double density (360kb). In this case the controller doesn't have to support 300 kbit/s transfer rate. All this means that in principle you can't use 1.2MB or 1.44MB drives in an XT because the controller won't support it. BUT, there are new (and improved :-)) controllers which do support these drives and transfer rates in an XT. These controllers must be accompanied by software, either on floppy (device drivers) or on ROM on the controller. Paul Derks Disclaimer: Anything I say can not and wil not be used against me!