And now I will present you one of the most exciting(for me) functions of the SymbiFace3: Total RAM/ROM control on the 4MB addressable space....
Thanks to Zozo's advice, Hans has been able to address all the Enterprise memory range. For the very first time on the Enterprise history, all the 256x16KB segments can be used. I know, there are very few programs that can use all that memory, but it is cool to be able to do it after all those years... and it works as planned, EXOS(with Dave aid)is able to work with few memory, exactly the same as with a lot of it. Rock solid operative system.
EPRAM[] is the command used to "inject" Ram on the segments between brackets. They can be named decimal, or hexadecimal if started with a "#". They can be listed with commas, but the most useful way to inject big zones of memory is as a range, first segment, hyphen(-), last segment.
ROM[] is similar, but injects only one Rom every time. The Rom can be 16KB, 32KB, 48KB or 64KB wide, SF3 will allocate the following segments, but we have to count them to not overwrite a segment. For example:
ROM[#60] =SD:SF3BOOT.ROM
ROM[#61] =SD:SPEMU128.ROM
ROM[#64] =SD:epd19uk.romSPEMU128 is a 48KB Rom, so in this case SF3 will use segments, 61h, 62h and 63h, so the user has to know that the next free segment is 64h.
As a convention, optionally, the 60h-6Fh zone has been designed for user Roms. On EXOS 2.0 and 2.1, only 60h, SF3.ROM will be visible, so other X0h segments should be used, as explained before.
But before starting to tweak on the Enterprise memory you should know more about your actual memory configuration.
The best way to know about it is to load EPDOS as extension. I provide the EPD17Z link on the museum
here. It doesn't work with the SD reader, but we only need its EXOS commands, not the program itself. Once loaded it will restart and load the EPDOS program, press A to abort and search Basic with the cursor and press Enter.
Once again in Basic execute :LRAM. and then :HROM. Some text like this will appear:
[ Guests cannot view attachments ]
On the Ram segments list usually you will not see the lowest segment, that has been allocated for the Z80 page 00. In this case it is F8h. Then you can count 8 Ram segments from F8h to FFh. This is a 128K UK model.
On the Rom segments list, EXOS is never shown only WP on segment 01h. You can see how EPDOS has been allocated on Ram zone FA-FBh, and also you can see that these segments are not on the free segments list.
The only Rom that is "out of place" is the EXDOS+ISDOS Rom, on 20-21h. But EXDOS takes for it all the 20-2Fh zone, so we can't add Ram or Rom there.
Now we are going to list the Ram/ROM segments that the SF3 could inject on a stock EP128:
05h-07h on the cartridge area(on a cartridge with language Rom also segment 05h is used, on the SD adapter all 04h-07h segments are used), 08h-1Fh and 30h-F7h. A total of 224 segments can be injected on a stock EP128 with EXDOS controller... 3584KB...
Just add these commands to the Ram setting section on the INI file:
EPRAM[#08-#1F]
EPRAM[#30-#F7]But as I have said, a stock EP128 has EXOS 2.1, so it will only search Roms on X0h boundaries. You will need to slice these big ranges to put some Roms on your EP.
I highly recommend you to upgrade your EP to the latest EXDOS from Zozo, because a lot of fixings and "modernizations" have been made on it, like the fast Ram check, very necessary if you don't want to sleep while all that "huge" amount of Ram is tested on the stock EXOS.... There is a turnaround for EXOS 2.0 and 2.1 users: to use the stand alone Zozo's memory fast check on a modified cartridge or on the SD-reader.
