Typingjust
SEQUENCE
without a number will print out the current sequence number.2. The sequence number is incremented by 1 for every me written or updated. This includes rtIes being copied, even though copied mes are not assigned a new number. In other words, each time you copy a me, the sequence will appear to skip a number; this is the number that would have been assigned to the copied file if it had not kept its old number.
3. Since the sequence number is just a single byte, the maximum number is 255, after which it returns to O.
SCAT arguments are the same as those for ACAT.
SK*DOS@ 68K USER'S MANUAL
SK*DOS09
SK*DOS09 is 6809 SK*DOS along with a 6809 CPU simulator which allows you to run 6809 SK*DOS programs on your 68K computer. This allows you to run programs which may not be available for the 68000, though at reduced speed.
To run SK*DOS09, simply type the command SK*DOS: SK*DOS09
As soon as the program runs, you will be greeted by the familiar SK*DOS signon, except that this time it will be 6809 SK*DOS that is running on your computer and the prompt will change to SK*D09:
Since your 68K computer is essentially interpreting 6809 instructions, you will notice a slight slowdown in operation. On input and output (such as listing a disk directory) you will hardly notice a difference, whereas on heavy computing there may be a significant slowdown, depending on the program being run. Even so, you may want to do certain operations (such as copying a disk) in 68K mode since that will always be faster.
SK*DOS09 will run most 6809 software, although there may be some programs which do not work. This will generally include those which access I/O hardware or other machine parameters directly, bypassing DOS. This includes, for example, programs which require interrupts, such as some text editors with type-ahead buffers. It also means that you cannot use a 6809 FORMAT program to format the disk - you must use the 68K FORMAT instead. Furthermore, although you might be tempted to use the 6809 SK*DOS's TIY command, don't bother;
I/O is handled by the 68K SK*DOS, and so use its IOCONFIG instead. There may be other programs which don't run as well - programs which use some particular characteristic of the 6809 CPU which is difficult or impossible to simulate on the 68K CPU. If you do run across some such example, let us know and we will try to suggest some other approach.
While running SK*DOS09, the ESCape key works normally to temporarily pause output; if you follow it with CR (or RETURN or ENTER, whichever it is called on your terminal), you will return to either SK*DOS09 or, in some cases, to the application program running under SK*DOS09.
Just as the MON command in normal SK*DOS/68K brings you 'back out one level' to the program which called it (namely the monitor or boot ROM), so MON in SK*DOS09 brings you out one level to the 68K SK*DOS when you want to exit.
Finally, a few technical details. SK*DOS09 requires a minimum 128K system, and devotes the entire second 64K of that system, from $1()()()() to $1FFFF, to simulating the 6809 environment. Each location of that 64K 'pseudo-memory' corresponds to the equivalent location of a normal 6809 computer system. (For example, the warm start location of 6809 SK*DOS is $CD03, while in SK*DOS09 it is located at $lCD03. The initial "1" is, however, totally transparent to 6809 software, which simply addresses that location as $CD03 as it always has done since the address translation is done entirely by SK*DOS09.) Just as in a true 6809 system, though, only the fust 56K is actually used; the last 8K, which would normally be taken up by 6809 I/O and monitor, is empty and available RAM.
In addition, SK*DOS09 also requires approximately 8K of user memory for its 6809 interpreter program. This normally starts at the current value of OFFSET.
SK*DOS09 uses your normal 68K I/O devices, and can access all your 68K disk drives, including RAM disk, although you must make sure that your RAM disk memory does not conflict with the memory used by
SK*DOS@ 68K USER'S MANUAL
SK*DOS09. If!t does, then SK*DOS09 will print an error message when it is started, indicating that there is not enough memory for it to function.
Since the disk formats for both 6809 and 68K SK*DOS versions are identical, 6809 and 68K ft.les can coexist on the same disk. You will note, however, that 68K command fIles have the extension .COM, whereas 6809 command ft.les use the .CMD extension. Hence typing a common command such as CAT or DELETE will always call the correct program. (Incidentally, both SK*DOSes will use the same ERRCODES.SYS fIle, since the error numbers are identical. Further, 6809 SK*DOS ignores .BAT fIles.)
Finally, SK*DOS09 can only access root directories (i.e., unnamed directories) of drives, since multiple directories were not available on 6809 SK*DOS systems.
SK*DOS (R) 68K USER'S MANUAL
STEPRAn:
The STEPRA TE command is used to set the speed at which SK*DOS commands disk drives to step from track to track. (Depending on your disk controller and disk drivers, this command may not exist, or may be slightly different.
For 5-1/4" disk drives, the allowable step rates are 6, 12,20, or 30 milliseconds (ms) per step (with most floppy disk controllers), or 2, 3, 12, or 20 ms (with the Western Digital 1772 controller). The step rate is specified after the word STEPRATE as in