The general syntax of the BACKUP command is:
BACKUP,<source drive #>,<destination drive #>[,CPU speed]
where <source drive #> is the drive holding the diskette to be backed up, <destination drive #> is the drive holding the diskette to be backed up to, and CPU speed is a "1" or "2" indicating the CPU clock rate assumed when the diskettes were formatted. (This is necessary because the Gimix FORMAT program has different interleave patterns for 1 Mhz and 2 Mhz CPUs. Backup uses the interleave pattern to read and write physically sequential sectors on the diskettes, so that an entire track can be reaad or written in one revolution.) This parameter defaults to 2. For example,
would copy the diskette in drive 0 to the diskette in drive 1, assuming a 2 Mhz type interleave. If the diskettes have different interleave patterns or the wrong pattern is indicated in the the command line, BACKUP will take up to 10 times as long to run. This may also happen if either diskette has a non-Gimix format. NOTE: The actual clock speed of the CPU is irrelevant; BACKUP is only concerned with the order of the sectors as set by FORMAT.
Before the copying begins, BACKUP prints the name of the destination disk in the follwoing prompt:
OKAY TO SCRATCH diskname.ext?
This is the last chance to abort BACKUP. The user must respond by typing "Y" or "N". If "N" is typed, BACKUP will be aborted and control retunrs to FLEX. If "Y" is typed, BACKUP will proceed. When BACKUP is done it sends three BELL characters to the console and prints "BACKUP COMPLETE!".
BACKUP will work with 5" or 8" drives, single or double density, and single or double sided formats. The number of tracks is obtained from the System Information Record of the source diskette; amy number is permitted provided both diskettes are the same. For more information on different disk formats see the FORMAT command.
BACKUP is much faster than COPY when a large number of files are copied. The approximate time required for BACKUP is given in the following table. These times assume a 56k system. Note that data density does not affect the time required.
|8" 77-track||5" 80-track||5" 40-track|
|single-sided||47 sec||82 sec||45 sec|
|double-sided||106 sec||130 sec||66 sec|
BACKUP checks a number of conditions before executing, and will abort if neccesary. When this happens "BACKUP ABORTED" is printed, followed by one of the following error messages.
PRINT SPOOLER ACTIVE - The BACKUP command cannot be used while the print spooler is active. The user must de-activate the spooler which the 'QCHECK' command or wait until all printing has finished.
INVALID DRIVE NUMBER - The user entered an illegal drive number for the source or destination drive.
HARD DISK NOT ALLOWED - The user attempted to back up to or from a hard disk device.
DEST DISK IS PROTECTED - The destination disk is write protected, either by hardware or software. This message will be generated if the destination disk is a 96-tpi drive emulating a 48-tpi drive, since Gimix FLEX 4.0 automatically protects such a drive.
DISKS ARE DIFFERENT SIZES - The user has attempted to back up a 5" diskette to an 8" diskette, or vice versa.
DISKS HAVE DIFFERENT FORMATS - The number of sectors per track or the number of tracks is different on the source and destination diskettes. Usually this means one diskette is double density or double sided and the other is not.
ILLEGAL DISK FORMAT - The number of sectors per track on either the source or destination diskette does not match and Gimix FLEX format. Only Gimix-formatted disks work properly with BACKUP.
ILLEGAL CLOCK RATE - The user specified a clock rate in the command other than 1 or 2 (Mhz).
NOT ENOUGH MEMORY - The system does not have enough user memory to store one full track (13k for SD/DD 8" diskettes, less for other formats).