roccella@pilot.njin.net (Matthew Roccella) (01/03/91)
Hello, I am trying to add a 1.2 Meg 5.25" disk drive to my COCO3. But I keep running into trouble. I made up a new drive cable, cut all the traces from my /D0 drive, accept the one that designates the drive as /d0, and I made a new OS-9 boot disk with the d1_80dd descripter. My trouble is that the system keeps giving me CRC errors and BAD SYSTEM TRACK errors. I cannot read, write, or format any disks in this new drive at all. My /d0 drive works fine. Doesn't the COCO3 take standard IBM type off disk drives? What kind of drive is compatible with the COCO3 and where can I get one at a good price? If anyone has added a disk drive to their COCO, please let me know what you did and how things have turned out. I'm racking my head as what to do next! Thank you, Matthew Roccella
yetsko@interlan.interlan.com (Mike Yetsko) (01/03/91)
The coco takes standard 360K floppies, not 1.2Meg. 360K floppies spin at 300rpm, 1.2M units spin at 360 rpm. While you CAN make stuff like 720K units work, they still use 250KHz clock rate. 1.2Meg floppies use 500KHz for 1.2Meg format and 300KHz data clock rates when doing 360K diskettes in the 1.2Meg drive. (300KHz clock at 360 rpm yeilds the same flux density as 250KHz at 300 rpm.) The Coco controller will only work at 250KHz. Mike Yetsko
jal@acc.flint.umich.edu (John Lauro) (01/03/91)
In article <Jan.2.12.25.00.1991.24309@pilot.njin.net> roccella@pilot.njin.net (Matthew Roccella) writes: > > I am trying to add a 1.2 Meg 5.25" disk drive to my COCO3. But >I keep running into trouble. I made up a new drive cable, cut all the >traces from my /D0 drive, accept the one that designates the drive as >/d0, and I made a new OS-9 boot disk with the d1_80dd descripter. > My trouble is that the system keeps giving me CRC errors and >BAD SYSTEM TRACK errors. I cannot read, write, or format any disks in >this new drive at all. My /d0 drive works fine. > Doesn't the COCO3 take standard IBM type off disk drives? What >kind of drive is compatible with the COCO3 and where can I get one at >a good price? If anyone has added a disk drive to their COCO, please >let me know what you did and how things have turned out. I'm racking >my head as what to do next! I doubt the CoCo can handle a 1.2 Meg drive as is. A high density drive requires a different controller chip, which is why you can't put a 1.2 meg drive in a PC without also replacing the controller. (286 AT class machines come with that type of controller.) You should be able to connect a 720k drive with little trouble. I don't know if a high density drive can act as a 720k drive or not. (Who knows, maybe the CoCo 3 controller does suppoer high density?) Are you sure you have the jumpers on the drive right? Most drives as bought these days come ready for PC compatables, which have the jumpers set differently then you would use for a cable with traces cut. (Personally I prefer setting the drive select jumpers to messing up a straight through cable.) Another thing to check is if you have one and only one terminator and it's on the correct drive. - John
a.dent@bluemoon.uucp (Bryan Hannahs) (01/08/91)
roccella@pilot.njin.net (Matthew Roccella) writes: > > Hello, > I am trying to add a 1.2 Meg 5.25" disk drive to my COCO3. But > I keep running into trouble. I made up a new drive cable, cut all the > traces from my /D0 drive, accept the one that designates the drive as > /d0, and I made a new OS-9 boot disk with the d1_80dd descripter. > My trouble is that the system keeps giving me CRC errors and > BAD SYSTEM TRACK errors. I cannot read, write, or format any disks in > this new drive at all. My /d0 drive works fine. > Doesn't the COCO3 take standard IBM type off disk drives? What > kind of drive is compatible with the COCO3 and where can I get one at > a good price? If anyone has added a disk drive to their COCO, please > let me know what you did and how things have turned out. I'm racking > my head as what to do next! > Thank you, > Matthew Roccella Hmm...well, first, if you got the motor running and the drive selected with your cable and such, I'd like to know what the changes were. I've got a 1.2meg I've been trying to use on my XT clone. It selects, but the motor won't run. Same thing happens when I try it on my CoCo. Does the drive work if you use a 360K (40 trk, DSDD) descriptor? If so, then it MUST be your descriptor. To the best of my knowledge, the CoCo controller only formats at double-density. This will allow you to get 720K (80 trk, DSDD) if all goes well. You won't be able to get the full 1.2meg as that requires more sectors per track than the CoCo can handle. The thing that puzzles me is that my XT's controller is SUPPOSED to be able to handle the 1.2meg AT drives. I think maybe I just have a jumpering problem, but I may need to twist the cable too. If it's just a matter of the motor select pin being in a different place, I'd try cutting the trace on the drive and moving it. I already have 3 360K drives for the CoCo, plus one in the XT, but it would be kinda nice to put a 720 on the CoCo even if I can't get it to work on the XT. 'Course, there should be no problem putting a 720K 3.5" drive on the CoCo, but I don't have any of them lyin' around at the moment... Bryan Hannahs (aka Arthur Dent) (BTW, please leave replies to me in comp.sys.tandy or comp.sys.m6809 as I don't generally read os9 stuff)
ingoldsb@ctycal.UUCP (Terry Ingoldsby) (01/18/91)
In article <RXweV6w163w@bluemoon.uucp>, a.dent@bluemoon.uucp (Bryan Hannahs) writes: > roccella@pilot.njin.net (Matthew Roccella) writes: > > I am trying to add a 1.2 Meg 5.25" disk drive to my COCO3. But > > I keep running into trouble. I made up a new drive cable, cut all the > > traces from my /D0 drive, accept the one that designates the drive as > > /d0, and I made a new OS-9 boot disk with the d1_80dd descripter. > > My trouble is that the system keeps giving me CRC errors and > > BAD SYSTEM TRACK errors. I cannot read, write, or format any disks in > > this new drive at all. My /d0 drive works fine. > Hmm...well, first, if you got the motor running and the drive selected > with your cable and such, I'd like to know what the changes were. I've got > a 1.2meg I've been trying to use on my XT clone. It selects, but the motor > won't run. Same thing happens when I try it on my CoCo. ... > thing that puzzles me is that my XT's controller is SUPPOSED to be able to > handle the 1.2meg AT drives. I think maybe I just have a jumpering I'm not sure about the second poster's problem (i.e. motor won't run), I suspect that there is either something wrong with the drive or you aren't getting the motor on pin wired correctly. The first problem is *easy*. What you don't realize is that the 1.2 MByte floppy disk drives spin faster (350 RPM ??) than the standard 80 track drives (300 RPM). Think about it. You start to lay down the format on the disk. Your CoCo thinks it knows how long it takes for the disk to spin so it writes out formatting info at that pace. Unfortunately for you the disk revolves more quickly and you overwrite the beginning of the track. Simple! There is nothing you can do to fix the controller, you must slow down the drive. Most 1.2 MByte disk drives use motors that have two speeds. Sometimes there is a jumper, sometimes a wire that must be disconnected to select 300 RPM. Do this and you will suddenly have a working drive. Your storage will only be about 700K, *not* 1.2 MByte. Have fun! -- Terry Ingoldsby ctycal!ingoldsb%cpsc.ucalgary.ca Land Information Services or The City of Calgary ...{alberta,ubc-cs,utai}!calgary!ctycal!ingoldsb
dclemans@mentorg.com (Dave Clemans @ APD x1292) (01/22/91)
From article <523@ctycal.UUCP>, by ingoldsb@ctycal.UUCP (Terry Ingoldsby): > The first problem is *easy*. What you don't realize is that the 1.2 MByte > floppy disk drives spin faster (350 RPM ??) than the standard 80 track > drives (300 RPM). Think about it. You start to lay down the format on the > disk. Your CoCo thinks it knows how long it takes for the disk to spin > so it writes out formatting info at that pace. Unfortunately for you > the disk revolves more quickly and you overwrite the beginning of the > track. Simple! > > There is nothing you can do to fix the controller, you must slow down the > drive. Most 1.2 MByte disk drives use motors that have two speeds. > Sometimes there is a jumper, sometimes a wire that must be disconnected > to select 300 RPM. Do this and you will suddenly have a working drive. > Your storage will only be about 700K, *not* 1.2 MByte. > To clarify things, 1.2 Meg drives DO NOT!! spin faster than other drives. The disk moves at EXACTLY the same speed. The difference between them is in the electronics. 1.2 Meg drives are clocked twice as fast as the slower drives. Controllers that can handle both drives have the ability to switch clock rates. dgc
wilker@gauss.math.purdue.edu (Clarence Wilkerson) (01/22/91)
Sorry to contradict the last posting, but 1.2 meg drives intended for IBM AT clones do spin at 360 RPM, with a data transfer rate of 300 K-bits per second, instead of the standard for older 5.25" drives of 250 kbs.at 300 RPM. Notice that if you write a disk on a drive at 250 kbs at 300 RPM, the bits have the same density as 300 kbs at 360 RPM. So diskettes written either way or interchangeable at the standard double density. However, when writing a 15 sector HD disk, the AT uses a data rate of 500 kbs, which is not quite twice the double density rate. Finally, the 1.44 meg 3.5" drives also use 500 kbs at 300 RPMs to pack 18 sectors on a track instead of the 9 at lower speed. Clarence Wilkerson
tony@mwuk.UUCP (Tony Mountifield) (01/22/91)
In article <1991Jan21.180211.11345@mentorg.com> dclemans@mentorg.com (Dave Clemans @ APD x1292) writes: > From article <523@ctycal.UUCP>, by ingoldsb@ctycal.UUCP (Terry Ingoldsby): > > The first problem is *easy*. What you don't realize is that the 1.2 MByte > > floppy disk drives spin faster (350 RPM ??) than the standard 80 track > > drives (300 RPM). Think about it. You start to lay down the format on the [.............] > > To clarify things, 1.2 Meg drives DO NOT!! spin faster than other drives. > The disk moves at EXACTLY the same speed. > > The difference between them is in the electronics. 1.2 Meg drives are clocked > twice as fast as the slower drives. Controllers that can handle both drives > have the ability to switch clock rates. In actual fact, what Terry said is correct. To clarify: At double density, both 3.5" and 5.25" drives run at 300rpm and are clocked at 250kHz. This gives the standard 720k storage. At high density, both types of drive are clocked at 500kHz. The 3.5" drive still rotates at 300rpm, so this gives exactly double the capacity, i.e. 1.44M. However, 5.25" drives in high density *ARE* rotated faster, at 360rpm. This is why they only give 1.2M instead of 1.44M - the rotation period is shorter. Both types of drive are normally switched between the two modes by a signal on pin 2. This switches timings in the electronics, and in the case of 5.25" drives also changes the motor speed. It is necessary for the disk controller to match its clock rate with the pin 2 setting. Tony. -- Tony Mountifield. | Microware Systems (UK) Ltd. MAIL: tony@mwuk.uucp | Leylands Farm, Nobs Crook, INET: tony%mwuk.uucp@ukc.ac.uk | Colden Common, WINCHESTER, SO21 1TH. UUCP: ...!mcsun!ukc!mwuk!tony | Tel: 0703 601990 Fax: 0703 601991 **** OS-9, OS-9000 Real Time Systems **** MS-DOS - just say "No!" ****
avalon@coombs.anu.edu.au (avalon) (01/23/91)
dclemans@mentorg.com (Dave Clemans @ APD x1292) writes: >From article <523@ctycal.UUCP>, by ingoldsb@ctycal.UUCP (Terry Ingoldsby): >> There is nothing you can do to fix the controller, you must slow down the >> drive. Most 1.2 MByte disk drives use motors that have two speeds. >> Sometimes there is a jumper, sometimes a wire that must be disconnected >> to select 300 RPM. Do this and you will suddenly have a working drive. >> Your storage will only be about 700K, *not* 1.2 MByte. >> >To clarify things, 1.2 Meg drives DO NOT!! spin faster than other drives. >The disk moves at EXACTLY the same speed. >The difference between them is in the electronics. 1.2 Meg drives are clocked >twice as fast as the slower drives. Controllers that can handle both drives >have the ability to switch clock rates. I have run a 1.2MB drive on my coco while using some utility program that shows disk rotation speed in RPM/ 1.2 drives go around at about 360+rpm and 720K drives at about 300 rpm (same as 360K drives). -avalon
slsw2@cc.usu.edu (01/26/91)
In article <avalon.664560280@coombs>, avalon@coombs.anu.edu.au (avalon) writes: > dclemans@mentorg.com (Dave Clemans @ APD x1292) writes: > >>From article <523@ctycal.UUCP>, by ingoldsb@ctycal.UUCP (Terry Ingoldsby): >>> There is nothing you can do to fix the controller, you must slow down the >>> drive. Most 1.2 MByte disk drives use motors that have two speeds. >>> Sometimes there is a jumper, sometimes a wire that must be disconnected >>> to select 300 RPM. Do this and you will suddenly have a working drive. >>> Your storage will only be about 700K, *not* 1.2 MByte. >>> > >>To clarify things, 1.2 Meg drives DO NOT!! spin faster than other drives. >>The disk moves at EXACTLY the same speed. > >>The difference between them is in the electronics. 1.2 Meg drives are clocked >>twice as fast as the slower drives. Controllers that can handle both drives >>have the ability to switch clock rates. > > I have run a 1.2MB drive on my coco while using some utility program > that shows disk rotation speed in RPM/ 1.2 drives go around at about > 360+rpm and 720K drives at about 300 rpm (same as 360K drives). 1.2 meg drives spin at 360 RPM because that's how fast 8" drives spun and a 1.2 meg drive has the same characteristics of an 8" drive. Really. IBM's original AT drive could not change speed, so it ran at 360 RPM regardless of the data rate. That's why an AT controller does 250 KHz, 500 KHz, and 300 KHz data rates; 250 is normal, 500 is 1.2 M, and 300 is normal in a 360 RPM drive. Good drives (TEAC FD55's, for instance) will change speed so that the disk controller only has to handle 500 KHz and 250 KHz. Oh yeah. I've noticed a tendency for PC drives to have the drive select jumpers soldered in at DS 1 since *everyone* has an AT and therefore *everyone* uses a twist in the cable so that all the drives are jumpered at DS 1. Being an old CP/M guy, this drives me nuts. Don't mind me; just passing through... -- =============================================================================== Roger Ivie 35 S 300 W Logan, Ut. 84321 (801) 752-8633 ===============================================================================