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« on: 2020.November.11. 10:32:38 »
I have not thought about it until recently: it is a pain to wait for the memory check on a stock Enterprise with lot of memory.
So this is the question: is there a way to skip the EXOS memory check with a SF3 connected?
Fortunately, yes. The solution comes from Zozo, of course, and his Fast memory check, that we can inject on segment 04(Cartridge memory are the 04-07 segment range) and will test the memory on a fraction of the time. It also brings us some other functions, like advanced tests, type and frequency of the Z80, and the enhanced WP2.6 text editor.
To install it we must left unplugged the Basic cartridge, and add the following lines to the SF3_EP.INI file:
ROM[4]=SD:EP/WP26.ROM
ROM[5]=SD:EP/BASIC21.ROM
Then download and place the following Roms on the SD:EP/ directory of your SF3 SD card.
Remember to not plug the cartridge on its bay while you have Roms injected with the SF3 on the cartridge addressing range, or it will cause a hang.
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Now, a little technical explanation about why Zozo's Fast memory check intercepts the original memory test:
One of the very first things that the EXOS Rom does when the Enterprise boots is to check if there is an special Rom on the 04 segment. Usually the first characters on a Rom header, for example on the Basic Rom, are "EXOS_ROM", but if that special Rom has the string "TEST_ROM", the boot process is halted and the control is passed to the program in the Test Rom.
This probably was useful on software/hardware development or on quality control after manufacturing the computer.
What Zozo's FastMemoryTest does is to perform its own test and then return the control to the EXOS Rom, but just on the point after the stock memory check is already done.