If you are having trouble with your Commodore disk drives, you might be interested in the repair and maintenance videos which I have for sale on the 1541 and 1571 disk drives. These are excellent "how to" videos that show you step by step how to check out the drives and then how to repair many problems. Each video is approximately 1 hour long. The price is $19.95 each or $34.95 for both of them. To order send e-mail to jaid@townsqr.com or call 1-800-308-3022 or send snail mail to Video Reflections, #1 Court Square, West Plains, MO 65775.
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#8 or #9?
From : Mike Vandenberg
Jean Parrot asks:
JP> There has to be one well edicated mind here that will come out with a patch that will seek to keep in memory the number of the drive used to boot a PRG. I know that Fritzterm does it and so does GEOS. FT will accept any number from 8 to 15 but GEOS only 8 or 9, but that is a start. As I was once writing here, it has to do with a PEEK(186) or a number close to that one. I forget which. My personal RAM again acting up. That PEEK (POKE) is in the putor and keeps a reference to the drive used..
10 x=peek(186)
That will give you the last serial device used. Just be sure you read it at the RIGHT time! (Immediately after loading from the device desired). Failure to do so may result in infinite loading times from your favorite printer.
A far simpler solution to the problem is something like this...
10 for x = 4 to 11
20 open15,x,15:close15
30 if st=0 then print "Device"x" present!"
40 next
Having your program do much the same will give your computer all the available serial devices, and from there you can have the user select which he/she wants to use.
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Lt. Kernal
From : Ron Fick
Some of the early Lt. Kernals used MFM drives with a build in SCSI controller board. They even had means to attach a tape backup. I'm currently the only source for new Lt. Kernals since I build them up from the remaining parts that I purchased from Xetec when they shut their doors. I have been building them up at a rate of about 1 a month for folks all over the nation and I'm enjoying it, just helping out the Commodore community. Unfortunately I don't have any info or software for that external SCSI controller board, but I suspect you're better off using an embedded controller SCSI drive nowadays anyway, although it would be nice to have the possiblity of a tape backup for the hard drive that the external controller provided.
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1571 HELP
From: Denise Fields
OK, another dumb question. Does the 1571 read both sides without flopping a disk?? know some PC's do that, and yes i read my 'book', but do not know what it is tlling me, I guess. Have only used 1541's before, and just realized from stuff I read here that the 1571 has 2 heads? The better to read you with (my dear9 to paraphrase???Or just to go bonkers?
told you it was a dumb question...but do need an answer.
From: Bill Marcum
Yes, the 1571 does read both sides of a disk, but only if it was formatted double-sided by a 1571. If the disk was made to be flipped on a 1541, you'll still have to flip it on a 1571.
From: El Phantas
Yes it does. There is a seperate head for each side. When the drive is in 1571 mode, you no longer have to think of a disk in terms of side one and side two. Its just one disk. The disk, however, must be formatted as a 1571 disk, and had whatever is on it written with a 1571. Your old 1541 disks still must be flipped over to read each side, and that includes most commercial software.
For more information about 1541 and 1571 modes, and how to change modes, see page 5-6 of the 1571 user's guide. Keep in mind that the user's guide assumes you are using the drive with a C128.
From: MICHAEL AURELIO
The 1571 does read both sides of the disk without flipping it over... Keep in mind that the double sided mode is commonly used in the Commodore 128 Burst mode..... However, I have been told that you can access double sided mode on the C64 ( nobody has told me how to do this yet )
From: CARLO TETA
Yes you do not have to touch the disk and it will read both sides
From: Jack Vander White
There are several parts to that answer.
1. Yes, the 1571 is capable of reading both sides of a disk.
2. On a 128 in 128 mode if you format a disk it will format in
double sided mode and have twice as many blocks as a 1541 disk.
3. On a 64, or if you go to 64 mode on a 128 by holding down the
logo key at startup It will switch to 1541 mode and read only
one side. If you format a disk in this mode it will format as a
1541 single sided disk.
4. It will not, in either 64 or 128 mode read the second side of a
1541 disk that was formatted by flipping it over unless you flip
it over.
5. There are a set of commands called "U" commands for the 1571
that you need to learn.
D#=Device Number, substitute the device number your 1571 is using for this.
SET 1541 MODE OPEN 15,D#,15,"U0>M0":CLOSE 15
SET 1571 MODE OPEN 15,D#,15,"U0>M1":CLOSE 15
SET to HEAD #0 OPEN 15,D#,15,"U0>H0":CLOSE 15
SET to HEAD #1 OPEN 15,D#,15,"U0>H1":CLOSE 15
If you set to 1571 mode in either 128 or 64 mode it will read, write and format the disk as a double sided 1571 disk with twice as many blocks. However, you can still only have 144 files on the disk.
If you set to 1541 mode in either 128 or 64 mode it will read, write and format the disk as a single sided 1541 disk. If you then set it to Head #0 and format and then set it to head #1 and format it will format each side as a 1541 disk and you can store 144 files on each side. However, what you put on side 2 can not be accessed by a 1541 disk drive. It will be recorded backwards to the way a 1541 reads.
There are several reasons why the use of the above is not recommended:
1. Some early 1571 ROMS have trouble accessing side 2.
2. When using a program it will cause problems unless the program is
set up to handle disks formatted this way.
3. There are very few copy programs that can copy data from/to disks
formatted this way.
: told you it was a dumb question...but do need an answer.
The only dumb question is the one you don't ask because you think it's dumb.
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1581 problem
From: Tom Cwikla
>Alan Jones (alan.jones@qcs.org) wrote:
>> I have an intermintent problem with my 1581 drive. It is still my most reliable drive, but the problem seems to be getting worse. Sometimes when I change diskettes I get the directory from the old diskette.
This is because once the 1581 reads the directory of a disk, it stores this directory in its RAM, and doesn't access the disk again until senses that a new disk has been put in. If you look inside your 1581, where the disk goes in, on the left side you will see two small white pins that stick up. These are actually tiny little switches that get pressed down when a disk gets put in. One of the switches detects the disk itself, the other one detects the write protect tab. Your problem is that one of these pins "sticks" in the down position when the disk is ejected and this makes the 1581 think that the same disk is still in the drive. To verify this, try ejecting a disk, and then check the directory with NO disk in the drive.
>> and is there a cheap or simple fix?
You can probably try to clean the switches with contact cleaner. I have never actually taken apart the switch assembly, I don't even know if it is possible. Another simple fix (although not so cheap) is to go down to your local PC store, and buy a regular IBM 720K drive, and simply swap it with the drive inside your 1581. You can also swap it with the drive out of an Amiga 500. I have actually done this and it does work. Of course opening up your 1581 voids the warranty but I assume its warranty is long over! :)
