Okay, here's the skinny: I've been using JS ROM code installed via a Tom Bent designed daughter board since about 1988 in my US/Samsung-made QL.
I've also used MGUK & MGUS (?) ROM code in my Samsung-made QL. I also have a pair of *real* JS ROMs for the day when the EPROM may give up the ghost ... AFAIK. There were no additional implementations to QDOS error code correction between the JS & JSU code. AND, the only change was the implementation of the TV-mode output. Al On Wed, 1 May 2002 16:24:08 +0000 (GMT) Dave <[EMAIL PROTECTED]> writes: > > > On Wed, 1 May 2002, Robert Newson wrote: > > > Al Feng wrote: > > > > > Essentially, when you swap QL ROMs, the video output for "TV" > mode > > > changes from NTSC to PAL and vice-versa for JSU & JS, > respectively. > > > > > > > Errm...don't the ROMs contain the CPU instructions...the video > output is > > shurely the job of other board chips (ZX8301, etc). > > > > However, (these are speculation/vague memories [of rumours?]) the > screen > > shape is different(?) and so the drawing routines would be > modified (so a > > CIRCLE is still a circle). Also, would the interrupt routine be > running at > > 60Hz as opposed to 50Hz, and so some timing routines would have > been rewritten? > > I suspect you're both right and both wrong. A US QL with US timings > would > have problems drawing a UK-resolution screen in the reduced time - > I > imagine the machine would slow down greatly. Similarly, I suspect a > UK QL > with US ROMs would speed up slightly. (Slower scan rate AND less to > scan) > > The question is based one xperimenting I'm doing with my US QL. > Nasta may > want to jump in, but I am also wondering what kind of headroom the > original QL mobos have for 'overclocking', in the sense of maybe > adding a > faster clocked 68008FN at 10-12MHz. I think the on-board RAM would > definitely fail at those speds and may have to be removed/neutered > ;) > > Finally, I'm thinking of putting up a web-based survey form asking > what > systems people use, so I can get an idea of the proportions of > different > system types out there. The results would help traders aim products > at the > right group of people (ok, at the expense of the hapless minority > still > using their original QLs with SPEM memory and DiRen kbd interfaces, > who do > all their programming in Forth ;) > > Dave > http://ql.spodmail.com/ > > > ________________________________________________________________ GET INTERNET ACCESS FROM JUNO! Juno offers FREE or PREMIUM Internet access for less! Join Juno today! For your FREE software, visit: http://dl.www.juno.com/get/web/.
