Instructions for using the cassette-recorder utilities

Abbreviations:

MLOS — unmanaged tape OS
JLOS — managed tape OS
CP/M — standard disk OS
BLOS — base tape OS

Programs:

	Purpose
FORM .COM	Format a tape and write the system
COPA .COM	Copy CP/M → JLOS, JLOS → CP/M, and CP/M → CP/M
COPM .COM	Copy CP/M → MLOS, MLOS → CP/M, and CP/M → CP/M When run under JLOS, also JLOS → MLOS and MLOS → JLOS
GENA .COM	Generate JLOS
GENM .COM	Generate MLOS
ATOS .SYS	Managed tape OS (not a load module)
MTOS .SYS	Unmanaged tape OS (not a load module)
SETS .COM	Display and change file statuses

FORM.COM

A program for formatting JLOS tapes and writing the system. It can be run under CP/M, JLOS, and MLOS.

FORMAT — format the tape.

• How many blocks should be written? If the answer is 0, the blocks must already have been written.
• How many blocks should be read? At least 8 blocks must be read.
• Verify the catalogue? After the catalogue is written to tape, it is read back and compared. If verification finds errors, the catalogue can be written to the tape again.
• Write the system? If an OS has been loaded with LOAD, the user can also write the system to tape after formatting.
• Verify the system? Verify the system that was written.

SYSGEN — write the system to tape.

• If the system is already loaded into memory, insert the tape on which it is to be saved.
• If the system has not been loaded, first read it from a system tape, then change tapes and save it.

LOAD — load a tape OS from a disk/tape file into memory.

• OS for a managed cassette recorder: ATOS.SYS
• OS for an unmanaged cassette recorder: MTOS.SYS

EXIT — exit the program.

• Ctrl-ESC always returns to the program's main menu.
• This program can also create MLOS system tapes: format only the first 8 blocks and save the MLOS system (MTOS.SYS).
• The program can also be run under MLOS to format tapes and put systems on them.
• If the program was started under JLOS, before exiting place in the cassette recorder the tape that was open when the program started.

COPA.COM

A program for copying files from disk to managed tape, tape to disk, and disk to disk. It can only be run under CP/M.

	Purpose
O - (OPEN)	Open the tape catalogue.
L - (CLOSE)	Close the tape catalogue; the catalogue remains open.
D - (DIR)	Display the disk/tape catalogue. A...D — disk drive T — tape
E - (EXIT)	Exit. If a tape is open, the program asks whether to close it.
R - (RESET)	Rewind the tape and reset the disks.
C - (COPY)	Copy files. First enter the source file name. If the file is not found, a message is displayed. Entering no name returns to the main menu. Next enter the destination file name (it may consist of only a device designator; the source name is then copied automatically). If the file already exists, the program asks whether to overwrite it. A negative answer prompts for the name again; a positive answer overwrites the file, even if its status is R/O. File names may use these device designators: A...D — disk drive T — tape If omitted, the default device is used.

COPM.COM

A program for copying files from disk to unmanaged tape, tape to disk, and disk to disk. It can be run under CP/M, and by an experienced user also under JLOS. Its dialogue is analogous to COPA.COM.

GENA.COM

A program for writing the managed tape OS. It can be run under CP/M and JLOS.

• Insert the source tape (the tape containing the system).
• After the system has been read, insert the tape on which it is to be written.
• Note: when exiting under JLOS, insert the tape that was open when the program started.
• Ctrl-ESC always returns control to the program.
• Ctrl-C interrupts the program.

GENM.COM

A program for writing the unmanaged tape OS. It can be run under CP/M, JLOS, and MLOS.

When using COPM.COM and GENM.COM, the following messages are displayed:

	Meaning
Set to Mtos	Initialise the unmanaged tape OS: remove the cassette-recorder control cable from socket X4.
Set to Atos	Initialise the managed tape OS: connect the cassette-recorder control cable to socket X4.

SETS.COM

A program for displaying and changing file statuses. It can be run under CP/M and JLOS. Under JLOS, displaying file statuses also shows the file's location (first and last block and length).

A>SETS [filename] [status]

	Values
status:	R/W — file can be read and written R/O — read-only file DIR — non-system file SYS — system file

JLOS functions

	Purpose
DIR [f]	List files
REN f1=f2	Rename a file f1 — new name f2 — old name
ERA f	Delete files
REST f	Restore a deleted file
MEM	Display general tape-space usage information
TYPE f	Display a text file
DUMP f	Display file contents in hexadecimal
LOAD f [a]	Load a file into RAM a — start address (default 100H)
RUN [p1] [p2]	Run the program in memory; parameters are stored in file control blocks
SAVE n f [a]	Save memory contents to a file n — number of 2K-byte blocks a — start address (default 100H)
CLOSE	Write the catalogue to tape; the catalogue remains open
OPEN	Read the catalogue from tape into memory
MONID	Exit the OS to the monitor
HELP	List resident functions
CHECK	Display system information and calculate a new catalogue checksum
DUMP ;a	Display RAM in hexadecimal a — start address
SAVE ;a	Modify RAM a — start address

Ctrl-C interrupts execution of a function.

Working with JLOS

The managed tape OS is operated in the same way as the standard CP/M disk OS.

MLOS functions

	Purpose
DIR	List blocks
TYPE f	Display a text file
DUMP f	Display file contents in hexadecimal
LOAD f [a]	Load a file into RAM a — start address (default 100H)
BLOAD [a]	Load blocks into RAM a — start address
RUN [p1] [p2]	Run the program in memory; parameters are stored in file control blocks
SAVE n f [a]	Save memory contents to a file n — number of 2K-byte blocks a — start address (default 100H)
MONID	Exit the OS to the monitor
HELP	List resident functions
DUMP ;a	Display RAM in hexadecimal a — start address
SAVE ;a	Modify RAM a — start address

Ctrl-C interrupts execution of a function.

Working with MLOS

When searching for a file (with LOAD, TYPE, DUMP, or while launching a load module), the headers of blocks that do not belong to that file are displayed.

If a user program uses BLOS function 17 (find file) or 18 (find next file), the following question is displayed on the first line:

FILE EXIST(Y/N) (Does the file exist?)

An affirmative answer means that a file with the requested name is assumed to be already present on the tape.

When function 20 (read a 128-byte block) or 42 (read a 2K-byte block) is invoked, the following text flashes on the first line for a few seconds: SWITCH TO READING. This means that the cassette recorder must be switched to playback mode.

If CHECKSUM ERROR is displayed while reading from tape, rewind the tape a little before retrying that block.

When function 21 (write a 128-byte block) or 43 (write a 2K-byte block) is invoked, the following text flashes on the first line for a few seconds: SWITCH TO RECORDING. This means that the cassette recorder must be switched to recording mode.

If STOP THE TAPE flashes on the first line, stop the tape.

DIR displays a 2K-byte block header:

n name m

	Meaning
n	Block number
name	File name
m	Number of the file's first block

When reading a managed tape:

	Meaning
n	Absolute block number
name	File name if the block belongs to a file; tape name if it is an empty block
m	0 if the block does not belong to a file; otherwise the file's first block number

When reading an unmanaged tape:

	Meaning
n	Block's sequence number within the file (starting at 0)
name	File name
m	Always 0

If no block header is found after reading the tape for 1.5 minutes, the error TIME OUT is displayed, meaning that the tape is empty.

Connecting the cassette recorder

The computer set includes a cable for connecting the cassette recorder. With a managed recorder, computer sockets X5 and X4 are used for data transfer and recorder control respectively. The recorder must not be in pause mode. With an unmanaged recorder, disconnect the cable from socket X4.