Empfaenger : /comp/sys/atari/8bit Absender : krishna@max.tiac.net (Glenn M. Saunders) Betreff : Re: multitasking - 6502? Datum : Sa 03.12.94, 08:14 (erhalten: 10.12.94) Groesse : 1301 Bytes -------------------------------------- Multitasking can get pretty intense. It isn't really that smart to set up a system were tasks are taking up 50/50 CPU time. The reason being that the odds are that one program isn't really doing much more than waiting for an input. So some form of intelligent monitor has to be written to figure out what a task is asking for and to give out its share of CPU time. And to assign PRIORITIES to each task. I believe even OS/9 goes this far into intelligent task management. With a slow processor, weeding out the 'waiting' programs and assigning them a low priority is crutial in maximizing throughput. I don't think Tom Hunt's MTOS went that far. It's quite easy to have dozens of tasks running and not have a drain on the CPU as long as the tasks are mainly waiting for some form of interaction. The benefit of having all of these code blocks in memory, is that if they can COMMUNICATE between processes, then you can save memory. You eliminate redundant code that way. I believe the term for some of this is REENTRANCY. It can get pretty complex, but although you might think that all this is a huge resouce drain, like I said, it can in fact reduce code size and can be a very efficient way to operate, if it is all working together integrated. Empfaenger : /comp/sys/atari/8bit, /comp/sys/cbm, /alt/folklore/computers Antwort in : /alt/folklore/computers Absender : jmayo@scu.edu.au (Joshua Mayo) Betreff : Re: Re 6502s (was Re: Why did Commodore beat Atari in the 8-bit m Datum : Sa 03.12.94, 07:43 (erhalten: 10.12.94) Groesse : 1229 Bytes -------------------------------------- Paul Guertin (guertinp@IRO.UMontreal.CA) wrote: : In article <3bi8p0$ims@ harm.magnus.acs.ohio-state.edu> rfunk@magnus.acs.ohio-state.edu (Rob Funk) writes: : > : >The 6502C was the version of the 6502 that the Atari used, which had : >some extra logic circuits on board. To use a standard 6502 or 65C02 : >in any Atari except early 400/800s, you need to add this extra : >circuitry. : Anyone know what exactly this extra circuitry is? Is the 6502C : pin-compatible with the 6502? Should be pin compatible... The difference between the 6502 and 65C02 is in the chip manufacture. The C in the number means the chip is CMOS as opposed to the NMOS original. these two manufacturing techniques result in different logic levels and need diffent interfacing. the other difference As I understand it is that because of the advanced Manufacturing techniques of CMOS the chips could actually be run at up to 3 Mhz... (This is only as I understand it, and I have looked in a few reference books, and tinkered in various forms of electronics...) CUL8R! -- ----- Josh Mayo. JMAYO@scu.edu.au - Commodore 64 FANATIC Öööö/ ^O-O^ ___________oOO_Öß/_OOo____________ Self Portrait. Empfaenger : /comp/sys/atari/8bit Absender : krishna@max.tiac.net (Glenn M. Saunders) Betreff : Re: multitasking - 6502? Datum : Fr 09.12.94, 23:26 (erhalten: 10.12.94) Groesse : 1334 Bytes -------------------------------------- Rick_Michael_Cortese@cup.portal.com wrote: : BTW John, I'm sure you could do a form of multitasking on the Atari : *IF* you wanted to. Something like word processing on terminals : hooked up to 2 or 3 serial ports on the PBI? Maybe I over estimate : your talents, but I'd bet you could knock something like that out : in an weekend. : Rick -- How about true parallel processing? There are some rough edges in the MUX, granted, but one thing it does have is pipes. These are PHYSICAL pipes between machines. These could very well act as an implementation of REXX ports. If you had an 8 slave MUX, with the right software, you could have 8 huge programs working together as one. Or several programs communicating with each other. The performance of such a multiCPU machine would be respectable enough to warrant following the project through. Far more powerful than timesharing a single 1.79mhz CPU. It just doesn't come cheap with the MUX... To date the only programs that use MUX pipes are Bob's infrequently used multiline chat on his board, and the multiline chat of multiline PRO!. Or you could take a cue from the Amiga and try to interface the Atari with a dissimilar CPU. There was talk at one time of hacking a 68881 FPU or DSP to the 8-bit through the PBI for instance. Empfaenger : /comp/sys/atari/8bit Absender : krishna@max.tiac.net (Glenn M. Saunders) Betreff : Re: Why did Commodore beat Atari in the 8-bit market? Datum : Fr 09.12.94, 23:29 (erhalten: 10.12.94) Groesse : 744 Bytes -------------------------------------- Winston Smith (winston@merk.com) wrote: : It was my understanding that IBM was subcontracted to fabricate the : ATARI JAGUAR boards, is this not so? Why would there be a quality : control problem ? (I'm curious....) I assume that IBM is a big : enough outfit that they can handle a sizable production run. IBM is infallible? I haven't the most faith in american workmanship. Not these days. It used to be the other way around, but it flip flopped in the mid to late '70s where american manufacturing quality dipped (especially with cars) and Japanese quaity soared. We are, after all, talking about .5 micron VLSI components. The first Pentiums weren't even .5 micron. It is a delicate manufacturing process. Empfaenger : /comp/sys/atari/8bit, /comp/sys/cbm, /alt/folklore/computers Antwort in : /alt/folklore/computers Absender : michaelb@hobbie.bocaraton.ibm.com (Michael Rogero Brown (Sys Admin Betreff : Re: Why did Commodore beat Atari in the 8-bit market? Datum : Fr 09.12.94, 22:29 (erhalten: 10.12.94) Groesse : 1074 Bytes -------------------------------------- James Finnegan (finneganj@delphi.com) wrote: : taylord@cs.man.ac.uk (David Taylor) wrote: : > While Sega, Nintendo and commodore often advertise on the TV do Atari,... No. : ^^^^^^^^^ : Geez, those Commodore ads must be wild, considering that they are : out of business! However, I agree that Atari's ads, developer support, : etc. is pitiful. He's probably talking about Commodore UK ads. The main Commodore company went belly up, but several of the subsidiaries, including Commodore UK are supposedly still going strong, from what I hear. I've even heard the C-UK wants to buy the rights to the Amiga so that it can still be manufactured and sold. -- ----------All Opinions Expressed are MINE, not IBM's-------------- Michael Rogero Brown (uK Development System Administrator) IBM (uK Development) TEL/TIE (407) 443-6400 Boca Raton, FL Internet: mikal@bocaraton.ibm.com If you think I speak for IBM, then I've got some swamp land^H^H^H^H^H^H^H^H^H^H real estate to sell you. Empfaenger : /comp/sys/atari/8bit, /comp/sys/cbm, /alt/folklore/computers Absender : stevesch@gate.net FogBottomPond Antwort an : stevesch@gate.net Betreff : Re: Why did Commodore beat Atari in the 8-bit market? Datum : Sa 03.12.94, 15:34 (erhalten: 10.12.94) Groesse : 448 Bytes -------------------------------------- In , guertinp@IRO.UMontreal.CA (Paul Guertin) writes: >In article <3biodc$qbb@news.iastate.edu> rhawkins@iastate.edu () writes: >> >>Apple II, II+, and IIe, 1Mhz 6502 1mhz > >1.023 MHz actually (North American versions -- I believe Eurapples Don't forget the 4 and 8 mhz ZIP chips that were plug-in compatible with the 6502s. Steve... "Who ran a BBS called the RainForest on a //e for 8 years" Empfaenger : /comp/sys/atari/8bit Absender : kendrick@zippy.sonoma.edu (William Kendrick) Betreff : Re: Mouse Handlers... Datum : Sa 03.12.94, 19:24 (erhalten: 10.12.94) Groesse : 326 Bytes -------------------------------------- I REALLY would like to see CardStax! :) Did you ever upload it to UMich!? -bill kendrick@vax.sonoma.edu ööö kendrick@zippy.sonoma.edu William (Bill) Kendrick / ö Ö ** New Breed Software ** PS - I've been playing with HyperCard lately.. neat.. could be better, but neat! I'd like to compare CardStax to it. Empfaenger : /comp/sys/atari/8bit, /comp/sys/cbm, /alt/folklore/computers Absender : scotts@rahul.net (S Mike Statton) Betreff : Re: Why did Commodore beat Atari in the 8-bit market? Datum : Sa 03.12.94, 19:28 (erhalten: 10.12.94) Groesse : 1067 Bytes -------------------------------------- In article <3bo0rn$39r@news.iastate.edu>, wrote: > >The ti wasn't exactly an 8 bit, though. It's processor ran a subset of >the LSI-11 set (PDP-11), and was at least nominally 16 bits, with a >32768 word address space. > Sir: Either you have never seen a PDP-11 or you've never seen a TI-9900. I have programmed both of these platforms, and they're NOTHING like each other. They're both 16-bit register-orientedÄ1Ü machines. There the similarity ends. Like the PDP-11 has a stack. The 9900 didn't. Subroutines used a register (traditionally R11) to store return addresses. Ä1Ü Yes, I know that the 9900 implemented the "register" file in main memory using the WP register. This made that processer really well suited to multi-tasking because you could swap out all of the registers in one swell foop. -- Scott Statton - N1GAK - Mountain View, CA - scotts@rahul.net Empfaenger : /comp/sys/atari/8bit Absender : esok@park.uvsc.edu (Eric Sokolowsky) Betreff : Dos XL and the Indus GT drive Datum : Sa 03.12.94, 19:25 (erhalten: 10.12.94) Groesse : 905 Bytes -------------------------------------- In article <3bfn8h$hce@usenet.INS.CWRU.Edu> aa700@cleveland.Freenet.Edu (Michael Current) writes: ... >Wasn't there a high-speed add-in module for DOS XL or something? I used >DOS XL way back when, but I never saw the drive use the Synchromesh until I >bought SDX. When I bought my Indus GT drive, it came with a version of DOS XL (I forget the version) and it had a little program that would turn on the high speed of the Indus drive. (GTSYNC ON was the command, I believe.) In the manual, however, there was a little blurb of a new program that would turn the high Indus speed on while loading DOS itself, as it was slower to load DOS from a high-speed disk, and the GTSYNC utility had to be loaded after DOS. But my DOS XL master disk didn't contain this new utility, despite the fact that the manual talked about it. Does anyone have this program? Is DOS XL supported anymore? Empfaenger : /comp/sys/atari/8bit Absender : krishna@max.tiac.net (Glenn M. Saunders) Betreff : Re: multitasking - 6502? Datum : Sa 03.12.94, 20:31 (erhalten: 10.12.94) Groesse : 1939 Bytes -------------------------------------- Multitasking is useful if you have the CPU power to support it. An 040 machine that can't multitask is a waste of available throughput. Machines of that power are more powerful than older mainframes. They have more than enough power to support multiuser environments, which are by very nature multitasking. Downloads are defininitely a dead time for the non multitasking machine. The #1 multitasking I do on my Amiga 1200 is during downloads. For instance, viewing pictures as each file completes itself from the batch download. Or uncompressing downloads as they come in file by file. This is a real time-saver as by the time the download is over I will have either saved off and/or installed or deleted the stuff I don't like. No time has been wasted waiting for the DL to finish. Another one is printing. Printing to inkjets can be slow depending on how you do it. This can tie up the machine if it won't multitask. Some word processors spawn a process to handle the print in the background I believe. Another is with graphics rendering. This can take a very long time. Essentially, any task that goes on without user input, is worthy of running in the background. Another is, let's say, having a FAX sentry look over one serial port, and having a multiserial board for a multiline BBS, and STILL be able to use the machine for your own personal applications. With the Atari 8-bit, it lacks the throughput to do some of these tasks at all, let alone have enough cycles left to support other tasks so the point may be moot. The best way to simulate some of this stuff on the Atari8 is to have a Multiplexer so you have multiple machines. It's just that during a download it may very well lock out the directory and/or drive it is writing to thus limiting your ability to process downloads as it is occuring. However, it is ideal for things like BBSs.