Virtual H89 Computer MMS 77316 Floppy Controller

The virtual MMS 77316 floppy controller allows up to 8 drives (4x 8" and 4x 5.25"). 5.25" drives may be "single track" or "double track" (40- or 80-track) and all drives may be single or double sided (1 or 2 heads). All drives can operate at single or double density. CP/M should allow reading of single-track disks in a double-track drive.

Configuration properties:

slot_p504, slot_p505, slot_p506

Any of these slots may be used to specify the floppy controller using the value "MMS77316".

mms77316_drive#

Specification of drive "#" type. Drives 1-4 are 8", 5-8 are 5.25". The following values are recognized:

FDD_5_25_SS_ST: Single-sided Single-track (40-track) 5.25" drive.
FDD_5_25_SS_DT: Single-sided Double-track (80-track) 5.25" drive.
FDD_5_25_DS_ST: Double-sided Single-track (40-track) 5.25" drive.
FDD_5_25_DS_DT: Double-sided Double-track (80-track) 5.25" drive.
FDD_8_SS: Single-sided 8" drive.
FDD_8_DS: Double-sided 8" drive.

A short string may follow the drive type, which will be used as the drive name in menus and on the front panel LEDs.

mms77316_disk#

Specify a pre-mounted floppy disk image in drive "#". Value is the path to the image file desired, followed by optional arguments. See notes for description of the "logdisk" image format. Arguments recognized:

rw: Mount floppy with writing enabled. Without this, the diskette (image file) will be read-only.

The "logdisk" (SectorFloppyImage) format is as follows:

The diskette image data is in the first part of the file, as simple contiguous sector data. There is no meta-data to separate sectors, tracks, sides, etc.
The last 128 bytes (not part of diskette capacity) contains a "header" which identifies the format. This record contains an ASCII LF-terminated string with the rest of the record filled with NULs (0x00). This string contains a series of numbers each terminated by a letter to indicate the meaning. An example for an MMS DD DS 5.25" diskette is "5m512z9p2s40t1d0i7l\n". The letters are interpreted as follows:

m

Media size, "8" or "5".

z

Sector size, 128, 256, 512, or 1024.

p

Sectors per track.

s

Number of sides (heads).

t

Number of tracks (40 or 80 for 5.25", only 77 for 8").

d

Density, "0" for single and "1" for double.

i

Interlaced, 0/1 for false/true. Indicates how the second side is used. Interlaced means that track 0 side 1 logically follows track 0 side 0. Non-interlaced means that track 0 side 1 follows track 39 (79, 76) side 0.

l

Latency factor. Not used by the image file itself, but is pertinent to certain low-level operations such as read/write track. This number is added to the current sector number in order to get the next sector number (modulo Sectors per track).

h

Hard sectoring. Non-zero indicates hard sectored media, number of sectors.

Image files may be created with the "format.jar" utility. Invoke as:

java -jar format.jar [options] <file> [format-options]

Invoke with no parameters to get help message:

Usage: format [options] <file> [format-options]
       format show [options] [format-options]
       format list
Options:
    files=d  = preload image with files from directory 'd'
    h8d=file = preload image from H8D file
    imd=file = preload image from IMD file
    td0=file = preload image from TD0 file
    list     = List all known formats
    show     = Show geometry(s) (do not format)
Format-Options:
    5 | 8
    DD | SD
    DS | SS
    DT | ST
    MMS | Z17 | M47 | Z37 | Z47 | Z67 | Z37X | Z47X

The <file> must not exist. A ".logdisk" suffix will be appended if not already specified. Format-Options must uniquely and specifically describe a valid format.

The "files=" option allows you to add local files to a fresh formatted image. Specify the directory containing the files. All files in that directory will be added. The files should conform to CP/M 8+3 (case insensitive) filename standards. Note that line endings are not modified, but files who's size is not a multiple of 128 bytes will be padded with ^Z (assumed to be text files). No file attributes are transferred, no CP/M-Plus features used, and no checking is made for duplicate file names. A file that begins with "#:", where "#" is a number 0-31, will be created under the specified CP/M user number. Files with no prefix are put in user 0.

The "h8d=" option allows you to overlay the newly formatted image with data from an H8D file. The new image must have the identical capacity as the H8D image.

The "imd=" option allows you to overlay the newly formatted image with data from an IMD file. The new image must have the identical geometry as the IMD image. Limited support for IMD formats.

The "td0=" option allows you to overlay the newly formatted image with data from a TD0 file. The new image must have the identical geometry as the TD0 image. Limited support for TD0 formats, does not support "advanced compression".

For "show", only one each of "h8d=", "imd=", and/or "td0=" may be specified, along with (optional) one set of Format-Options. No image file is specified, no images are created.