wa60@sdcc12.UUCP (paul van de graaf{}) (03/17/86)
I recently upgraded my 800XL to 256K using a revised version of the Byte article mod. The new version pages in memory in 16K chunks, and is pretty much compatible with XE software. I'd guess it's similar in design to the CDY 256KXL upgrade. It's 8-256K RAM chips, and either 3 or 5 TTL chips de- pending on which ANTIC chip you have. I built it for $35.00 and an afternoon of my time. If you're interested in this mod, check with your user-group -- mine printed it in their newsletter. I would have posted it, but I doubted I could ASCII-fy the scematic. Anyway, I'm using the patch to DOS 2.5 that was posted to Usenet a while back. It is supposed to give you two 720 sector ramdisks. Well... I tried it and I'm having a few problems. Sure enough, I have 2 ramdisks, but I'm getting some errors from DOS when the ramdisks get close to full. It appears that somehow files near the end of the disk get corrupted and their file numbers get changed somehow. This gets DOS upset, and renders the files unuseable. My guess is that somehow the wrong memory page gets bank-switched in, or the ramdisk gets overwritten. I haven't looked into it too closely. Has anyone else had this problem? For a while there I was suspecting the hardware, but I did some memory tests and could find nothing wrong. I'll be glad to try and find a patch to DOS 2.5, if I can confirm that it's a software problem. To duplicate the problem on your system, copy a disk with about 700 sectors on it to D8, and then try to copy the files on D8 to a blank disk. IE. C(opy) D1:*.*,D8: then C(opy) D8:*.*,D1:. By the way, did anyone try the homebrew Action! run-time library I posted here a couple of weeks ago? I expected some kind of response to it, but nada. In the past, UCSD has had some problems with postings not getting out of the local net. Perhaps it's happened again. The posting is ~400 lines long, so I hesitate to post it again. Send me mail in either event, as I can't be sure this post will get out either! Paul van de Graaf sdcsvax!sdcc12!wa60 U. C. San Diego
DYOUNG@USC-ISID.ARPA (C. David Young) (03/24/86)
Paul, I saw nothing about a homebrew ACTION! runtime library but I sure would like to get hold of it! Please post it again or at least send me a copy. Thanks, David Young -------
jhs@MITRE-BEDFORD.ARPA (03/26/86)
I have been running two ramdisks in my 800XL with CDY's 256KL upgrade. Actually, one of them has been a 130XE compatible 500+ sector one and the other a standard SD 720-sector one. I have noticed no problems, but I can't swear that I have really filled them both up at the same time. With 256K, it is possible to implement two 720-sector ramdisks, as this takes only 186320 bytes for the storage, and you have 196608 bytes to work with. But obviously there isn't room for error! I.e. all 16K segments will be used! -John Sangster jhs@mitre-bedford.arpa <..anypath!ihnp4>!linus!mbunix!jhs