LOWMEM.THD --- Copyright 1987 by Phil Wheeler An original compilation of Compuserve Model 100 Forum messages for use by Forum members only. James Yi recently uploaded the file LOWMEM.200 telling how to block off a range of low RAM in the 200 in order to install a converntional machine langurage program in residence down there. This short thread file contains some incidental discussion of his approach and (mainly!) a message which gives the addresses needed to use the same approach on the Model 100/102. At this time (7/8/87) no reports of M100 usage have been received. Message range: 151401 to 151423 Dates: 7/1/87 to 7/1/87 Sb: #LowMem.200 upload Fm: James Yi 73327,1653 To: Tony Anderson 76703,4062 Uploaded LOWMEM.200 inn dL10.. James Fm: Tony Anderson 76703,4062 To: James Yi 73327,1653 Thanks for the contribution, James... breaking new ground here. I'm sure Phil, Denny, and some of the other machine language programmers will be making this available for the Model 100/102 very quickly. We appreciate you work on this. Fm: Phil Wheeler 71266,125 To: Tony Anderson 76703,4062 Seems like the Great ynoT suggested something of the sort a bit ago. Or am I mistaken? Hmmm..compared to the usual low raom techniques (0MENU, MACPGM, SUPERA, POWR-DOS) this may allow less constained files -- with nulls, for example. Should be easy enough to try with the 100, given the address comparisons. Fm: Tony Anderson 76703,4062 To: Phil Wheeler 71266,125 Yes, I do recall pointing out the possibility of something like this working... but never followed up on it. James did, and deserves the credit. I think the idea is neat! It gives you an effective extension of the ROM. Theoretically, you could even relocate a DOS to those lower addresses. Fm: Phil Wheeler 71266,125 To: Tony Anderson 76703,4062 NIce idea James has, again! Alas -- jsut occured to me that there is no way to test it without some software to stuff down there! Plus must use my backup m100 -- dubious if 0MENU & SUPERA will (load and) run under such a set-up. I imagine the 200 world is less rife with low RAM pseudo-Basic m/l programs. Fm: Phil Wheeler 71266,125 To: Tony Anderson 76703,4062 In case anyone wants to try James Yi's LOWMEM.200 on the Model 100, here are the address translations: Line 200 Address 100 Address ---- ----------- ----------- 10 40960 32768 20 40960 32768 40 62702 64192 40 62703 64193 50 64799 65451 50 64798 65450 In the related notes: 40961 becomes 32769, and 61109 becomes 62965. Now, having documented all this, I have to tell one and all that I have not yet tried it. But look at it this way: Since you have to do a clod start to install the patch in the first place, the worst result is a cold start of an already wiped machine! Low risk, to say the least! Fm: Tony Anderson 76703,4062 To: Phil Wheeler 71266,125 Reassemble and stuff MACROS.PGM down there.... in fact, it may not even be necessary to reassemble, just load it and hide 255 bytes. Fm: Phil Wheeler 71266,125 To: Tony Anderson 76703,4062 But I already have MACPGM attached to X-TEL. Hmmmm...could stuff one of my tiny m/l pgms there -- or even ASMBLR.CO. Or... . Oh well, for me it will remain a novelty, due to use of 0MENU in all 8 banks.