cmm1@cunixa.cc.columbia.edu (Christopher M Mauritz) (06/02/90)
From cunixf.cc.columbia.edu!rutgers!ucsd!sdd.hp.com!cs.utexas.edu!sun-barr!newstop!texsun!alanya!lupe Thu May 31 01:12:59 EDT 1990 Article 16099 of comp.sys.amiga: Path: cunixf.cc.columbia.edu!rutgers!ucsd!sdd.hp.com!cs.utexas.edu!sun-barr!newstop!texsun!alanya!lupe >From: lupe@alanya.Central.Sun.COM (Lupe Christoph - Sun Germany Consulting - Munich) Newsgroups: comp.sys.amiga Subject: Atari ST emulation, the first review (long) Summary: Review of the first commercial emulation of the Atari ST on the Amiga. Keywords: Atari ST, emulation Message-ID: <lupe.644089476@alanya> Date: 30 May 90 17:44:36 GMT Sender: news@texsun.Central.Sun.COM Lines: 162 This is a quickly done translation of the first review of Medusa, the Atari ST emulator for the Amiga 2000. Please excuse the probably rough English. I don't believe that I'm required to produce Marketese ;-) I have left the prices in Deutschmarks since this news group is quite international. Most people are probably aware of their exchange rates with the Dollar, so here is the exchange rate for Deutschmarks to Dollar: 1 $ is roughly 1.67 DM. New perspectives from an Atari in the Amiga Atari ST Computers are technically inferior to the Amiga in Video and Audio. Despite this, they have won a quantitative and qualitative advantage in areas like text processing. After inserting Combitec's emulation card Amiga users can employ the powerful software of the seemingly weaker computer. Following Readysoft's emulator A-MAX another emulator makes new worlds acessible to the Amiga. Instead of trying to imitate the Apple Macintosh, Combitec's Medusa tries to emulate the Atari ST as closely as possible. Somebody imagining the emulator as a complete Atari ST on a plug-in card will be surprised. On the small Medusa card for the 100 pin Amiga-slot he will nmainly find two logic components (PALs) that enable the Atari ST software to use Amiga hardware. WIth this the purchase of Atari hardware is superfluous und possibly ensuing copyright problems are avoided. Medusa requires an Amiga with at least 1 Megabyte RAM and a diskette drive. Combitec recommends a 2 MByte RAM expansion to be able to work with programs that require more memory. The emulator uses the entire Amiga memory without problems. Also used are all interfaces, the diskette drives (read and write-compatible with original Atari 720 KB drives) and certain hard disks. Printers and plotters can be used, too. The owner of a well equipped Amiga owns also a well equipped Atari. After inserting the card Medusa can be started immediately. The software can be loaded directly from diskette or hard disk and is not copy protected. The Amiga part of the software consists primarily of the Medusa program - the emulator proper - and the installation software that is needed especially for using a hard disk. The Atari operating system TOS (Tramiel Operating System) - not included in the package - can be stored on hard disk and be loaded from there. Owners of a Combitec filecard or a Combitec AutoBoot card can create a bootable parttion of their hard disk for the Atari ST. A short and clear installation program facilitates TOS installations on Amiga diskettes or hard disks, theassignment of Amiga diskette drives to the Atari, the creation of an Atari partition on hard disk and the adjustment of video refresh. The problem of getting the operatin system of the emulated computer is prevailing among emulators. For the Macintosh emulator A-MAX the original Macintosh ROMs are required, but cannot be delivered with it for copyright reasons. For Medusa this problems can be solved relatively easily: For one the dealers are seling Ataris TOS as a diskete version for 15 DM, and a program called "GetTOS" is delivered with Medusa that, started on an original Atari ST, reads the TOS out and writes it to diskette. This diskette can be used for the emulator directly or as a medium for the hard disk installation. Sources for the diskette TOS are referred to by Combitec on request. Combitec points out that the legal questions have to be checked out before copying the TOS. In doubt Atari has to be asked for permission ! For the test the TOS version 1.0 was available on diskette. According to Combitec the capability is planned to put the ROM-TOS into sockets on the Medusa card. Since TOS can be loaded from hard disk in a few seconds, this plan was shelved for now. In daily use this solution provides greater flexibility since users can choose between different TOS versions that can all be stored on hard disk. After installation a typical Atari desktop screen appears on the Amiga monitor. Since HiRes mode is pre-selected it is an interlace screen. The characteristical flicker is somewhat abated as the refresh frequency of the monitor (1084 et al.) can be increased from 25 Hz to 31 Hz or even 35 Hz for better devices. This facility does not require a special Agnus chip. In LoRes or MedRes logically the double of the HiRes frequency can be used, up to 70 Hz. This represents an absolutely stable image. One has to experiment to find the ideal value: an accessory included with Medusa (a program that can be reached at any time on the Atari ST) allows the variation of the setting from the emulator. If the screen is showing a wild image instead of the normal screen the monitor cannot keep up. Very useful in this procedure is the feature that allows to switch back to the standard Amiga setting (this is always working) at any time. "Signum! 2", the extremely successful scientific text processing package, is an important program to find out about compatibility and flawless function of the emulator. Texts could be processed and printed without perceptible difference in speed. With the progres of the test this impression got firmer. Programs like Calamus, Arabesque, Tempus and Tempus Word, STAD, GFA-BASIC, Adimens, Psion Chess and Turbo C ran without problems like on the original ST. Even the software accelerator Turbo-ST ran and helped Medusa to a fantastic text output speed. As the shareware performance program Qindex ran, too, it was possible to test the speed of Medusa: 95 to 98 percent of the original speed were attained. Under Turbo-ST Medusa peeked to 1160 percent of an original ST without Turbo_ST. But the limits of the emulator became visible, too: third emulations like Aladin, the Macintosh emulator for the ST computer, did not run. Many games did not run likewise. This is pointed out in the manual, because if a program assumes certain hardware prerequisites that are not present in the Amiga - like the original ST diskette drives with index hole controlled hardware - and uses this hardware circumventing the operating system, this environment cannot always be emulated. Combitec expect direct user participation on enhancing Medusa because of a one year, no-cost update service. The manufacturer says they are dependent on cooperation with manufacturers of hardware and software to support more hard disks or software protected by dongles, like that in the midi market, to make Medusa workable. As said, Medusa works without problems with memory expansions, diskette drives and hard disks. Flicker fixer cards do not disturb the emulator likewise. But it is not possible to use the emulation if 68020 or 68030 cards are installed. This is not because of Medusa, but because of TOS: The present TOS versions run with the 68000 processor only. Combitec is waiting for new TOS versions, like that for the long announced Atari TT. There are already deliberations to run the Atari as a screen on the Amiga. To speed up the emulator, a card called "Piccolo" is announced that with provide a 14 MHz 68000 and 256 KByte to 1 MByte memory. The memory is designed with SRAM so that switch-off resistent storage of Kickstart or TOS in fast RAM is possible. (J. Sprave/rg) The Combitec development "Medusa" is sold by MacroSystem, Gahlenfeldstrasse 6, 5804 Herdecke, Germany. Phone +49/23 30/80 11 32. The price is DM 498. ------------------------------------------------------------------------ The German version of this article was published in Amiga Welt 6/90, pp 50/51. This translation does not reflect the opinions of the translator, who is only a reader of that magazine and in no way related to either the publisher or Combitec or MacroSystem. I did this translation because many people have been talking about Atari emulation on comp.sys.amiga. I do not want to purchase this system myself and please don't flame me if you don't like the contents of this article of the rough cut translation. -- | lchristoph@Sun.COM (Internet) | Disclaimer: | | ...!unido!sunmuc!lupe (German EUNet, "bang") | My employer has a | | lupe@sunmuc.UUCP (German EUNet, domain) | non-exclusive license | | ...!suninfo!lchristoph (Sun Germany customers) | to my opinion. | ------------------------------+--------------------------- Chris Mauritz |Donde hay una cerveza cmm1@cunixa.cc.columbia.edu |hay un plan. (c)All rights reserved. | Send flames to /dev/null |El Guerrero Aereo es el rey! ------------------------------+---------------------------