576



576            240            DFLAGS
     Disk flags read from the first byte of the boot file (sector one) of
     the disk.

577            241            DBSECT
     The number of disk boot sectors read from the first disk record.

578,579        242,243        BOOTAD
     The address for where the disk boot loader will be put. The
     record just read will be moved to the address specified here,
     followed by the remaining records to be read. Normally, with
     DOS, this address is 1792 ($700), the value also stored
     temporarily in RAMLO at 4, 5. Address 62189 ($F2ED) is the OS
     disk boot routine entry point (DOBOOT).

580            244            COLDST
     Coldstart flag. Zero is normal, if zero, then pressing RESET will
     not result in reboot. If POKEd with one (powerup in progress
     flag), the computer will reboot whenever the RESET key is
     pressed. Any non-zero number indicates the initial powerup
     routine is in progress.

If you create an AUTORUN.SYS file, it should end with an RTS
instruction. If not, it should POKE 580 with zero and POKE 9 with one.
You can turn any binary file that boots when loaded with DOS menu
selection "L" into an auto-boot file simply by renaming it
"AUTORUN.SYS". Be careful not to use the same name for any two
files on the same disk.

When this is combined with the disabling of the BREAK key discussed
in location 16 ($10) and the program protection scheme discussed in
location 138 ($8A), you have the means to protect your BASIC
software fairly effectively from being LISTed or examined, although
not from being copied.

581            245            ....
     Spare byte.

582            246            DSKTIM
     Disk time-out register (the address of the OS worst case disk time-
     out). It is said by many sources to be set to 160 at initialization
     which represents a 171 second time-out, but my system shows a
     value of 224 on initialization. Timer values are 64 seconds for
     each 60 units of measurement expressed.
     It is updated after each disk status request to contain the value of
     the third byte of the status frame (location 748; $2EC). All disk
     operations have a seven second time-out (except FORMAT),
     established by the disk handler (you had noticed that irritating
     little delay, hadn't you?). The "sleeping disk syndrome" (the