Posted By
MMS
on 2023-12-30
18:36:05
 |  Re: Looking for Plus/4 games on floppy
With JiffyDOS the 1581 is a beast, fast and big.
No, burst mode does not work ok Plus/4, though theoretically it is possible to implement it on the same way as on C64, to involve the CIA (in our case ACIA) for the task, but it needs two wires and the complete rewrite of the C64 code.
https://commodore.software/downloads/download/8-programming-tutorials/1417-c64-burst-mode
I have Jiffy for my Plus/4, and planning to build the 1581 for myself with the help of project available on PCBWay too.
Only one thing annoys me a little, that the JiffyDOS switches off the screen on +4, makes the loading process for eg BASIC games a continuous blinking experience.
I know Jiffy can reach higher speed if the whole screen can be used for the handshake and fast transfer (and no badlines, etc), but I think it took the easy way.
I would be happy enough with a slower Jiffy speed but switched on screen during loading, like load only when the TED is on bottom or upper border area.
I know the speed could be only the 40% of the current, but would be still 7x faster, than an 1541 normal load, and 2x faster than an 1551 loading speed and the loading would not influence the customer experience so much.
Also I need to mention, that during the tests with the emulators I found the Jiffy on +4 to be a little unstable, but I will see how it will performs with the real HW.
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