The SamRam is a hardware device Johan and I built for our Spectrums. It consists of a 32K static RAM chip which contains a modified copy of the normal Basic ROM and a number of other useful routines, like a monitor and snapshot software. You can compare it to a Multiface I interface, but it's more versatile. Another useful feature was a simple hardware switch which allowed use of the shadow 32K Ram, present at 8000-FFFF in most Spectrums, but hardly ever actually used.
For more details on the low-level hardware features of the SamRam read chapter 5. In this chapter I'll explain the software features of the SamRam software, somewhat bombastically called the `SamRam 32 Software System' or the `Sam Operating System'. By the way, all similarity between existing computers is in fact purely coincidental and has in no way been intended. Really!
The SamRam offers a few new Basic commands, and a lot of useful routines that are activated by an NMI, i.e. by pressing F5. First I'll discuss the Basic extension.
Select the SamRam by starting the emulator with the -s switch, or by selecting it from the F9 menu. Normal Basic functions as usual; the character set is different from the original one. There are four new commands:
*RS, *MOVE, *SAVE and *SPECTRUM,
|
DEC and HEX, which have replaced
ASN and ACS. DEC takes a string argument
containing a hexadecimal number, and returns the decimal value of it.
HEX is the inverse of the DEC function, and yields a
four-character string.
*RS sends its arguments directly to the RS232 channel.
You don't have
to open a "b" or "t" channel first. You're right, it's of limited use.
Example: *RS 13,10
*MOVE is useful: it moves a block of memory to another place.
Example: *MOVE 50000,16384,6912 moves a screen-sized block from
50000 to the start of the screen memory.
*SAVE works like *MOVE, except that it activates the shadow
SamRam ROM
before moving. I used this command to update the shadow ROM, but on the
emulator you can use it to move the shadow ROM to a convenient place in
Ram where you can take a look at it, for instance by executing
*SAVE 0,32768,16384.
*SPECTRUM resets the SamRam Spectrum to a normal one. You lose
all data
in memory. By resetting the emulator by pressing ALT-F5, the SamRam is
activated again. Not very useful either.
SAVE!, LOAD!, CAT!, ERASE!
and FORMAT!. The syntax is
straightforward. FORMAT! and CAT! need no parameters;
ERASE! only needs
a name. If a file is not found, the SamRam will respond with a 5-End of
File error. The Ramdisk has a capacity of 25K.