Xref: utzoo unix-pc.general:3541 comp.sys.att:7254 Path: utzoo!utgpu!watmath!uunet!tut.cis.ohio-state.edu!att!laidbak!botton From: botton@laidbak.UUCP (Brian D. Botton) Newsgroups: unix-pc.general,comp.sys.att Subject: KIT OFFER & Re: hardware solution for direct access to video ram Keywords: kit, video ram, Mgr, X, device drivers Message-ID: <2586@laidbak.UUCP> Date: 10 Aug 89 02:31:10 GMT References: <2575@laidbak.UUCP> <586@uncle.UUCP> Reply-To: botton@laidbak.UUCP (Brian D. Botton) Organization: Interactive Systems Corporation, Naperville, IL Lines: 72 In article <586@uncle.UUCP> jbm@uncle.UUCP (John B. Milton) writes: >In article <2575@laidbak.UUCP> botton@laidbak.UUCP (Brian D. Botton) writes: >... >>JOHN: Why didn't you try a software (loadable device driver) approach? >I was refering to an everything in the driver aproach, where access would still >be fast, but your point is well taken. It is wonderful to be able to work on >drivers the way we can on this machine, but it's still a bitch next to regular >user level programs. The idea is begining to grow on me, which does bring up a ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ >bit of a delema as far as how I'm going to implement the screen part of the ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ >X server. ^^^^^^^^^ Glad to hear it, hope it's contagious :-). Yeah, user level code is SOOOOO much nicer to deug. I have received a number of e-letters saying that they found the idea interesting, but since they weren't hardware hackers they were reluctant to give it a try. I want to reiterate, this daughter board makes NO modifications to ANY boards on the 3B1/7300. This was the single most important design goal. One person thought my original posting said I was reluctant to program pals, and to be honest I was a little (okay, very) vague. I wanted to see what kind of response this generated before I started making offers. I posted those long instructions just in case someone wanted to go ahead and give it a try, even if they haven't built a pc board before. Plus, I feal that everyone should know what's involved in making a custom pc board. Don't let it scare you away, it just takes time and patience. So, what does this boil down to? Brad's and mine (mostly Brad's) port of Mgr is going to rely on this little board, so if you are thinking of using Mgr you'de better give this board a bit of serious thought. Well, X people, if John is thinking this over, what do you think? If there was enough interest I would be willing to put together a kit that includes all the parts that would be needed. And because I understand that the initial investment to buy all the junk needed to etch one little board is pretty high, I am willing to investigate a commercially etched pc board. It seems to me that if widely supported ports of Mgr and X are to succeed it will have to be easy to get this board. What will this cost? I haven't the slightest idea, but probably in the $30 - $50 range. I'll do some checking around to find out what pc board manufacturing costs are going for in the Naperville (Chicago far west suburb) area. I should also be able to simplify the design with a commercial board, such as a single sided pc board and no 64 pin socket, and thus keep the cost down. I know there are people working on X at this time and I would hate to see a lot of effort lost because of a change in midstream. I'll start checking tomorrow and try to post some cost figures within a couple of days. In the mean time, send me e-mail if you are interested. If there are enough people in on this to even come close to breaking even I'll go ahead with providing kits, pal, pc board, and instructions included. If we're lucky it might be done in less than a month. > >> 8. I don't know if I should mention this, but I don't see any reason >> to hide it. The displayable portion of the video does not use up >> all of the video ram. So we also have an automatic shared memory >> segment at the end of video ram. BUT, it is wide open and you're >> probably a fool to use it and an idiot to rely on it. > >I WAS hoping you wouldn't (mention) it, but it is 32768-31320=1448 bytes... ^^^^^^^^^^^^^^^^^^^^^^^^^ Yeah, I know, I debated for a while about that one. But figured we're all adults and what we do in the privacy of our own computer . . . Besides, I DO keep your process's grubby little mits from mucking with the disk controllers, OBM, page tables . . . -- ... ___ _][_n_n___i_i ________ Brian D. Botton (____________I I______I laidbak!botton /ooOOOO OOOOoo oo oooo