Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!ut-emx!ccwf.cc.utexas.edu!greg From: greg@ccwf.cc.utexas.edu (Greg Harp) Newsgroups: comp.sys.amiga.advocacy Subject: Re: advice please - Atari-ST or Amiga Message-ID: <44108@ut-emx.uucp> Date: 12 Feb 91 23:53:11 GMT Sender: news@ut-emx.uucp Reply-To: greg@ccwf.cc.utexas.edu (Greg Harp) Organization: The University of Texas at Austin Lines: 65 Originator: greg@pooh.cc.utexas.edu My news reader choked every time I tried to follow up to this post, so I had to re-post it. Jari Lehto writes: In article <43991@ut-emx.uucp> greg@ccwf.cc.utexas.edu (Greg Harp) writes: >Jari, I don't want to call you a liar, but maybe you'd better describe that >"multitasking" OS a bit better. It sounds like a simple task-switcher to >me. Multitasking means that all of the programs are running at once. You don't have to. It is no switcher, you just have to select which window is the active one. You can only do things with the active one. Others remain running at the backround. You can also do things at the unactive windows by holding down the right mouse-button. Only thing it doesn't do is updating the unactive windows during process. But when for example a download is ready on a terminal, it updates the window to let you know about this. Well, that certainly sounds better than other multitasking implementations on otherwise single-tasking machines. This OS is a German beta-version, a very restricted one. I am not allowed to give any further details out! >BTW, your statement that every multitasking OS requires huge amounts of >memory and a fast CPU is simply wrong. My A500 still has the stock 7.14Mhz >68000 in it. I have 3.5MB of RAM, but I use 1.5MB of it as a recoverable >RAM-Disk, and I have 1.3MB free. That means that I am using about 700K of >memory and I have 10 CLI-processes alone running. In all, there are 21 >tasks currently running on my system. I use this particular setup every >day, and the machine still works as if each program is the only one running. >That's basically due to the provisions made in the OS that eliminate CPU- >intensive programming techniques such as busy-waiting fo keyboard input. The need of speed and memory is because programs for ST are not planned to be run in a multitasking-OS. They reserve certain amount of memory to run and if they can't get it, they will crash. Speed is needed for... You must know! I had Cubase and Calamus running simultaneously, that definitely was slow! Especially when I tried to output to laser from both simultaneously. It worked, but was very slow indeed! That's the problem with trying to multitask in a machine that doesn't have proprietary multitasking. You see, on the Amiga programs use the OS routines to do I/O and other tasks that might conflict with other programs. When a program wants keyboard input, for example, the it tells the OS to wake it up when a key is pressed and then goes into a sleep stage. On other systems that don't normally multitask, the program would just sit there and poll the keyboard until a key is pressed. Busy-waiting is what eats up most of the speed of a multitasking system, so it is avoided on the Amiga. The rest of the OS is designed with a similar philosophy, so what you get is clean, fast multitasking without the need for tons of memory or a super-fast CPU. I could easily run Pro Page, Excellence, and DPaint while using my multi-shell terminal. I wouldn't even notice a loss of speed since these programs, although ready for input at any time, are not taking CPU time. Jartsu *** Jari Lehto, jartsu@otax.hut.fi, s37837k@saha.hut.fi *** Greg -- ------------------------------------------------------------------------------ "I don't know what it is I like about you, but I like it a lot." -- Led Zeppelin, Communication Breakdown -------Greg-Harp-------greg@ccwf.cc.utexas.edu-------s609@cs.utexas.edu-------