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Posted By

Jay
on 2001-05-24
 1581 on a Plus 4?

Hi gang, I am new to the Plus 4 - so new that I haven't connected any disc drives to it yet. I know it's compatible with the 1541, but how about the 1581?

Also, does it format disks compatible with the 64? Can they read each other's formats?

Thanks!

Posted By

RĂ¼diger
on 2001-08-08
 1581 DOS

Hi James,

the 1581 have DOS 10.0 and not 3.0!! Please look again!!

RĂ¼diger

Posted By

James
on 2001-05-24
 A Triumphant 'Yes!!!'

The 1581 is compatiable with the Plus/4 and siblings C16/116. In fact, it is compatiable with all CBM 8-bit computers that use the CBM serial bus. If you have the 1581 already, the book has some typos, but it is the ONLY post-Plus/4 literature that mentions compatiability with the Plus/4 series computer.

To answer the second question: the 1541/1551 use 5.25" diskettes, the 1581 uses 3.5" diskettes.

Now, more info on the first question:

Basically, the 1581 book assumes that the BASIC commands that deal with the disk drive are the same as the 128's. That is pretty much true except for the BLOAD/BSAVE commands and the RECORD command. These functions will require your using the C64 (BASIC 2.0) equivalents.

DS$ at power-up will result in "CBM DOS V3.0 1581", so any prorgams that require a specific DOS (DOS 2.6 1541) will have to be modified. This would be limited to disk utilities like a BAM viewer, or direct disk-access programs.

Copy-protected programs will most likely not work, as the 1581 uses a different disk layout and sectors will not line up in the same place; also the DOS code is different enough that certain copy-portection routines will not be in the same place as the 1541/1551.

The Plus/4 does not support the burst commands available on the 1581 or 1571. You will have to have a 128 or 128D for that chapter.

Supposedly the save-with-replace bug is fixed with the 1581, but I always save under a new filename, scratch, then rename, just to be safe. (From what I've read, if you use "@0:filename" you won't have any problems.)

Partitioning the disk (very similar to subdirectories on your Mac or IBM/compatiable hard drive) is possible but a pain in the backside with the software on the 1581 Test/Demo diskette. The root directory of the 1581 will hold up to 296 file entries, which is over twice what the 1541's directory will hold. Actual storage is 3160 blocks unless partitions or direct-access files are used (over 4 times what a 1541 will hold)!

I love my 1581, especially now that 5.25 diskettes are so hard to find new these days!

James



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