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mg_notes:cpm:softcard_cpm_ref [2019/06/17 14:25] M.G. [Typing at the Apple Softcard CP/M Keyboard] |
mg_notes:cpm:softcard_cpm_ref [2019/09/30 18:29] (current) M.G. [The Apple CP/M Disk Parameter Tables] |
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| ^ Key ^ Action ^ | ^ Key ^ Action ^ | ||
| - | | <key>Ctrl-\S</key> | Temporarily stops character output to TTY: Output is resumed when any character is typed | | + | | <key>Ctrl-'S'</key> | Temporarily stops character output to TTY: Output is resumed when any character is typed | |
| | <key>Ctrl-P</key> | Sends all character output to LPT: as well as to TTY: \\ This "printer echo" mode remains in effect until another <key>Ctrl-P</key> is typed. | | | <key>Ctrl-P</key> | Sends all character output to LPT: as well as to TTY: \\ This "printer echo" mode remains in effect until another <key>Ctrl-P</key> is typed. | | ||
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| ^ Offset ^ Contents ^ Use ^ | ^ Offset ^ Contents ^ Use ^ | ||
| - | | 00H | SPT 16b | Total number of sectors per track | | + | | 00H | SPT 16b | Total number of 128-byte sectors per track | |
| - | | 02H | BSH 8b | Data allocation block shift factor, determined by the data block allocation size | | + | | 02H | BSH 8b | Data allocation block shift factor, determined by the data block allocation size \\ 3 -> 1K, 4 -> 2K, 5 -> 4K, ... | |
| - | | 03H | BLM 8b | Data allocation block mask (2[BSH-1]) | | + | | 03H | BLM 8b | Data allocation block mask (2[BSH-1]) \\ 7 -> 1K, 0FH -> 2K, 01FH -> 4K, ... | |
| | 04H | EXM 8b | Extent mask, determined by data block allocation size and number of disk blocks | | | 04H | EXM 8b | Extent mask, determined by data block allocation size and number of disk blocks | | ||
| - | | 05H | DSM 16b | Total storage capacity of disk drive | | + | | 05H | DSM 16b | Total storage capacity of disk drive, blocks minus one | |
| | 07H | DRM 16b | Total number of directory entries minus one | | | 07H | DRM 16b | Total number of directory entries minus one | | ||
| - | | 09H | AL0 8b | Determines reserved directory blocks | | + | | 09H | AL0 8b | Directory allocation bitmap, byte 0. | |
| - | | 0AH | AL1 8b | Determines reserved directory blocks | | + | | 0AH | AL1 8b | Directory allocation bitmap, byte 1. | |
| | 0BH | CKS 16b | Size of directory check vector | | | 0BH | CKS 16b | Size of directory check vector | | ||
| | 0DH | OFF 16b | No of reserved tracks at beginning of logical disk | | | 0DH | OFF 16b | No of reserved tracks at beginning of logical disk | | ||
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| bit of AL1, 15=lo bit of AL1. Bits are assigned starting at bit 0 up | bit of AL1, 15=lo bit of AL1. Bits are assigned starting at bit 0 up | ||
| until bit 15. Suppose nbits is the number of bits set to 1: | until bit 15. Suppose nbits is the number of bits set to 1: | ||
| + | |||
| + | |||
| ^ BLS ^ Directory entries ^ | ^ BLS ^ Directory entries ^ | ||
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| | 16384 | 512 * nbits | | | 16384 | 512 * nbits | | ||
| - | Example: if DRM=127 (128 directory entries) and BLS=1024 bytes, there | + | Example: |
| + | |||
| + | ^ ^ AL0 ^^^^^^^^ AL1 ^^^^^^^^ | ||
| + | ^ Bit ^ 7 ^ 6 ^ 5 ^ 4 ^ 3 ^ 2 ^ 1 ^ 0 ^ 7 ^ 6 ^ 5 ^ 4 ^ 3 ^ 2 ^ 1 ^ 0 ^ | ||
| + | ^ Value | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | | ||
| + | |||
| + | If DRM=127 (128 directory entries) and BLS=1024 bytes, there | ||
| are 32 directory entries per block, requiring 4 reserved blocks. Thus | are 32 directory entries per block, requiring 4 reserved blocks. Thus | ||
| the 4 hi bits if AL0 are set, and AL0=0FH, AL1=00H | the 4 hi bits if AL0 are set, and AL0=0FH, AL1=00H | ||
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| ^ Physical format: ^ A ^ B ^ C ^ D ^ | ^ Physical format: ^ A ^ B ^ C ^ D ^ | ||
| - | ^ ^ Apple CP/M ^^ Enhanced ^ Standard ^ | + | ^ ^ Apple CP/M ^^ Enhanced CP/M ^ Standard \\ CP/M ^ |
| - | ^ ^ 13-sect ^ 16-sect ^ 80-trk/16-sec/2-side ^ 8" SSSD ^ | + | ^ ^ 13-sect ^ 16-sect ^ 80-trk \\ 16-sec \\ 2-side ^ 8" SSSD ^ |
| | Bytes/sector | 256 | 256 | 256 | 128 | | | Bytes/sector | 256 | 256 | 256 | 128 | | ||
| | Sectors/track | 13 | 16 | 16 | 26 | | | Sectors/track | 13 | 16 | 16 | 26 | | ||
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| **Apple CP/M DPB - Disk Parameter Block** | **Apple CP/M DPB - Disk Parameter Block** | ||
| - | ^ ^ A ^ B ^ C ^ D ^ ^ | + | ^ ^ A ^ B ^ C ^ D ^ ^ |
| + | ^ ^ Apple CP/M ^^ Enhanced \\ CP/M ^ Standard \\ CP/M ^ ^ | ||
| | SPT 16b | 26 | 32 | 32 | 26 | 128-byte Logical Sectors/Track | | | SPT 16b | 26 | 32 | 32 | 26 | 128-byte Logical Sectors/Track | | ||
| | BSH 8b | 3 | 3 | 4 | 3 | Block shift factor | | | BSH 8b | 3 | 3 | 4 | 3 | Block shift factor | | ||