Commodore 1581 filesystem - Revision history

Dan Tobias at 03:24, 22 April 2014

2014-04-22T03:24:34Z

Dan Tobias at 03:22, 22 April 2014

2014-04-22T03:22:17Z

Dan Tobias at 03:21, 22 April 2014

2014-04-22T03:21:31Z

Dan Tobias: Created page with "{{FormatInfo |formattype=electronic |subcat=Filesystem }} The '''Commodore 1581 filesystem''' is a variant of CBMFS used in the 3.5" disks for the Commodore 1581 disk ..."

2014-04-22T03:20:52Z

Created page with "{{FormatInfo |formattype=electronic |subcat=Filesystem }} The '''Commodore 1581 filesystem''' is a variant of CBMFS used in the 3.5" disks for the Commodore 1581 disk ..."

New page

{{FormatInfo
|formattype=electronic
|subcat=Filesystem
}}
The '''Commodore 1581 filesystem''' is a variant of [[CBMFS]] used in the 3.5" disks for the [[Commodore 1581 disk]] drive. This was less common in the Commodore community than the 5.25" [[Comodore 1541 disk]]s and [[Commodore 1571 disk]]s. Because of the different number of sectors, the Block Allocation Map (BAM) was arranged differently.

Track 40 (of the 80 logical tracks) contained the BAM and directory. 40/0 was a header sector, and 40/1 and 40/2 had the BAM, with the directory starting on 40/3.

== Header sector (40/0) ==

* 00-01 (hex): Track and sector of first directory entry (40/3)
* 02: DOS version ('D')
* 03: unused
* 04-13: Disk label, padded with $A0 bytes
* 16-17: Disk ID
* 19-1A: DOS type ('3D')

== BAM 1st sector (40/1) ==

* 00-01: Track and sector of next BAM sector (40/2)
* 02: DOS version ('D')
* 03: unused
* 04-05: Disk ID
* 06: I/O byte
* 07: Autoboot flag
* 10-FF: BAM entries for tracks 1-40 (6 bytes per entry)

== BAM 2nd sector (40/2) ==

* 00-01: 00/FF (presumably the next BAM track/sector would be here if there were one)
* 02: DOS version ('D')
* 03: unused
* 04-05: Disk ID
* 06: I/O byte
* 07: Autoboot flag
* 10-FF: BAM entries for tracks 41-80 (6 bytes per entry)

[[Category:Commodore computers]]

← Older revision		Revision as of 03:24, 22 April 2014
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	Track 40 (of the 80 logical tracks) contained the BAM and directory. 40/0 was a header sector, and 40/1 and 40/2 had the BAM, with the directory starting on 40/3.		Track 40 (of the 80 logical tracks) contained the BAM and directory. 40/0 was a header sector, and 40/1 and 40/2 had the BAM, with the directory starting on 40/3.
		+
		+	This sort of drive also supported dividing disks into multiple partitions as a fixed-allocation form of subdirectories.

	== Header sector (40/0) ==		== Header sector (40/0) ==

@@ Line 3: / Line 3: @@
 |subcat=Filesystem
 }}
-The '''Commodore 1581 filesystem''' is a variant of [[CBMFS]] used in the 3.5" disks for the [[Commodore 1581 disk]] drive. This was less common in the Commodore community than the 5.25" [[Comodore 1541 disk]]s and [[Commodore 1571 disk]]s. Because of the different number of sectors, the Block Allocation Map (BAM) was arranged differently.
+The '''Commodore 1581 filesystem''' is a variant of [[CBMFS]] used in the 3.5" disks for the [[Commodore 1581 disk]] drive. This was less common in the Commodore community than the 5.25" [[Commodore 1541 disk]]s and [[Commodore 1571 disk]]s. Because of the different number of sectors, the Block Allocation Map (BAM) was arranged differently.
 Track 40 (of the 80 logical tracks) contained the BAM and directory. 40/0 was a header sector, and 40/1 and 40/2 had the BAM, with the directory starting on 40/3.

@@ Line 35: / Line 35: @@
 * 07: Autoboot flag
 * 10-FF: BAM entries for tracks 41-80 (6 bytes per entry)
 [[Category:Commodore computers]]