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Changed DiskDump to deal better with disk images that are physically larger than the disk's logical file system (specifically, 320Kb FAT images inside 360Kb disk images, and 160Kb FAT images inside 180Kb disk images); the Lotus 1-2-3 v1.0a disks I dumped from my personal collection are the perfect example.

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Jeff Parsons 2017-07-04 13:35:50 -07:00 • committed by Jeff Parsons
commit c4a8d66027
11 changed files with 188 additions and 80 deletions
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20
modules/shared/lib/diskapi.js
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@ -133,7 +133,7 @@ DiskAPI.BPB = {
TOTAL_FATS: 0x010, // 1 byte: FAT copies (eg, 2)
ROOT_DIRENTS: 0x011, // 2 bytes: root directory entries (eg, 0x40 or 64) 0x40 * 0x20 = 0x800 (1 sector is 0x200 bytes, total of 4 sectors)
TOTAL_SECS: 0x013, // 2 bytes: number of sectors (eg, 0x140 or 320); if zero, refer to LARGE_SECS
MEDIA_TYPE: 0x015, // 1 byte: media type (see DiskAPI.FAT.MEDIA_*)
MEDIA_ID: 0x015, // 1 byte: media ID (see DiskAPI.FAT.MEDIA_*); should also match the first byte of the FAT (aka FAT ID)
FAT_SECS: 0x016, // 2 bytes: sectors per FAT (eg, 1)
TRACK_SECS: 0x018, // 2 bytes: sectors per track (eg, 8)
TOTAL_HEADS: 0x01A, // 2 bytes: number of heads (eg, 1)
@ -146,21 +146,21 @@ DiskAPI.BPB = {
*
* Each entry in GEOMETRIES is an array of values in "CHS" order:
*
* [# cylinders, # heads, # sectors/track, # bytes/sector, media type]
* [# cylinders, # heads, # sectors/track, # bytes/sector, media ID]
*
* If the 4th value is omitted, the sector size is assumed to be 512. The order of these "geometric" values mirrors
* the structure of our JSON-encoded disk images, which consist of an array of cylinders, each of which is an array of
* heads, each of which is an array of sector objects.
*/
DiskAPI.GEOMETRIES = {
163840: [40,1,8,,0xFE], // media type 0xFE: 40 cylinders, 1 head (single-sided), 8 sectors/track, ( 320 total sectors x 512 bytes/sector == 163840)
184320: [40,1,9,,0xFC], // media type 0xFC: 40 cylinders, 1 head (single-sided), 9 sectors/track, ( 360 total sectors x 512 bytes/sector == 184320)
327680: [40,2,8,,0xFF], // media type 0xFF: 40 cylinders, 2 heads (double-sided), 8 sectors/track, ( 640 total sectors x 512 bytes/sector == 327680)
368640: [40,2,9,,0xFD], // media type 0xFD: 40 cylinders, 2 heads (double-sided), 9 sectors/track, ( 720 total sectors x 512 bytes/sector == 368640)
737280: [80,2,9,,0xF9], // media type 0xF9: 80 cylinders, 2 heads (double-sided), 9 sectors/track, (1440 total sectors x 512 bytes/sector == 737280)
1228800: [80,2,15,,0xF9], // media type 0xF9: 80 cylinders, 2 heads (double-sided), 15 sectors/track, (2400 total sectors x 512 bytes/sector == 1228800)
1474560: [80,2,18,,0xF0], // media type 0xF0: 80 cylinders, 2 heads (double-sided), 18 sectors/track, (2880 total sectors x 512 bytes/sector == 1474560)
2949120: [80,2,36,,0xF0], // media type 0xF0: 80 cylinders, 2 heads (double-sided), 36 sectors/track, (5760 total sectors x 512 bytes/sector == 2949120)
163840: [40,1,8,,0xFE], // media ID 0xFE: 40 cylinders, 1 head (single-sided), 8 sectors/track, ( 320 total sectors x 512 bytes/sector == 163840)
184320: [40,1,9,,0xFC], // media ID 0xFC: 40 cylinders, 1 head (single-sided), 9 sectors/track, ( 360 total sectors x 512 bytes/sector == 184320)
327680: [40,2,8,,0xFF], // media ID 0xFF: 40 cylinders, 2 heads (double-sided), 8 sectors/track, ( 640 total sectors x 512 bytes/sector == 327680)
368640: [40,2,9,,0xFD], // media ID 0xFD: 40 cylinders, 2 heads (double-sided), 9 sectors/track, ( 720 total sectors x 512 bytes/sector == 368640)
737280: [80,2,9,,0xF9], // media ID 0xF9: 80 cylinders, 2 heads (double-sided), 9 sectors/track, (1440 total sectors x 512 bytes/sector == 737280)
1228800: [80,2,15,,0xF9], // media ID 0xF9: 80 cylinders, 2 heads (double-sided), 15 sectors/track, (2400 total sectors x 512 bytes/sector == 1228800)
1474560: [80,2,18,,0xF0], // media ID 0xF0: 80 cylinders, 2 heads (double-sided), 18 sectors/track, (2880 total sectors x 512 bytes/sector == 1474560)
2949120: [80,2,36,,0xF0], // media ID 0xF0: 80 cylinders, 2 heads (double-sided), 36 sectors/track, (5760 total sectors x 512 bytes/sector == 2949120)
/*
* The following are some common disk sizes and their CHS values, since missing or bogus MBR and/or BPB values
* might mislead us when attempting to determine the exact disk geometry.