Re: Found a place where you can download lisa images

From: James MacPhail <gg__at_email.domain.hidden>
Date: Sat, 14 Apr 2007 03:34:17 -0700

>> You can make perfectly usable images from any classic Mac, 68K or PPC >>that has a GCR capable floppy drive, IF you use Disk Copy 4.2.

Note the subtle emphasis: *IF* (you use DC4.2). Using DiskCopy 4.2 is the key to making this work.

> what then about the 3-5 bit timing problems with the newer drives?
> or is that just something disk copy 6 introduces

I presume you mean the bitslip FF problem (which originally appeared with the arrival of the MacII: disks written by a MacII would sometimes fail in a Lisa). This is not a function of the floppy drive, but the driver used to write to the disk.

DiskCopy 4.2 uses its own methods for writing to the disk hardware, and it always uses 5 bitslip FFs, so disks made by DiskCopy 4.2 will be readable by the Lisa Floppy Disk Controller.

The problem with DART is that it uses the system's driver, which on a MacII or later will use 3 bitslip FFs.

Note: This is not only an issue with formatting and writing a disk image. ANY data written to a disk by a driver that is using 3 bitslip FFs might not be readable on a Lisa. Except for DiskCopy 4.2, that means any MacII computer or newer.

Just mounting and ejecting an unlocked (Macintosh) disk in the Finder can cause some information to be writen, which can make the floppy unreadable on a Lisa.

You can use DC 4.2 to "fix" disks that are unreadable due to this problem: Read the disk as a master image using DC4.2, then write it all back to the disk; DC4.2 will use 5 bit-slip FFs when writing, regardless of the original image.

The problem with DiskCopy 6, as far as I understand, is that the tag bytes are always set to zero. Some Lisa disks have special information in the tag bytes, such as the indication that it is a bootable disk. This is a completely different problem than the bitslip FFs, and DiskCopy 4.2 cannot fix this problem.

HTH, James

--~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "LisaList" group. To post to this group, send email to lisalist_at_email.domain.hidden To unsubscribe from this group, send email to lisalist-unsubscribe_at_email.domain.hidden For more options, visit this group at -~----------~----~----~----~------~----~------~--~--- Received on 2007-04-14 03:37:46

This archive was generated by hypermail 2.4.0 : 2020-01-13 12:15:21 EST