Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!ccu.umanitoba.ca!herald.usask.ca!alberta!ubc-cs!uw-beaver!cornell!batcomputer!caen!zaphod.mps.ohio-state.edu!think.com!mintaka!geech.gnu.ai.mit.edu!rjc From: rjc@geech.gnu.ai.mit.edu (Ray Cromwell) Newsgroups: comp.sys.atari.st Subject: Re: Amiga is better then what??? Message-ID: <1991Jun28.205724.1752@mintaka.lcs.mit.edu> Date: 28 Jun 91 20:57:24 GMT References: <1991Jun27.200127.23004@informatik.uni-erlangen.de> <1991Jun27.211005.9179@mintaka.lcs.mit.edu> <1991Jun28.124442.15920@informatik.uni-erlangen.de> Sender: news@mintaka.lcs.mit.edu Organization: The Internet Lines: 68 In article <1991Jun28.124442.15920@informatik.uni-erlangen.de> csbrod@immd4.informatik.uni-erlangen.de (Claus Brod) writes: >rjc@geech.gnu.ai.mit.edu (Ray Cromwell) writes: > >> The Amiga's filesystem isn't at like the ST/IBM PC format. But >>filesystems are only the higher level organization of data. The Amiga >>(and it's new HD drive) can write MFM tracks out exactly like >>720k/1.44mb IBM disks, or 880k/1.72mb Amiga disks. For instance, on >>my Amiga, I merely mount an MS-DOS filesystem and I can read/write >>IBM disks from any application as if ithere was nothing different. > >I know quite a bit about the Amiga's filesystem, but I didn't know >the new HD drives can write a genuine PC MFM format. Tnx for the >information. This must have been done by using intelligent drives, >I suppose. The Filesystem has alittle to do with the density of the drive. All the file system cares about are block numbers. What controls the drive is the trackdisk.device. For instance,a normal 880k disk has 1738 sectors and the Filesystem might ask the trackdisk.device to read block 1600 (which may be a part of a file, a directory sector, whatever) The new drives in the 3000 are variable speed drives like the Mac, so the drive motor can be slowed to 1/2 speed giving twice the density without a more expensive drive head or a new controller chip. So all the new system does is check if your using an HD disk and switch drive speeds. Writing PC format is no problem in the HD mode. >> Well, you don't need any internal hardware to use it. You just buy >>a $499 monitor. The refresh rate is 15hz, yes, but it's not bad. >>The monitor is meant for publishing/cad/text applications, not >>animation. The Amiga can send out one 768x240x4 screen every 60th of a >>second (or 768x480x4 interlaced at 30hz) This is 92,160 bytes of data. >>A 1024x1024x2 (or 1008x800x2) is about ~200,000 bytes. So it takes >>~3.2 frames to transfer a screen to the A2024. I guess C= rounds it up to >>4 so the A2024 updates at 15hz. > >And how many cycles does this cost for the CPU? Zero CPU cycles. The display doesn't eat CPU cycles as long as you have fast ram. A more appropriate question would be to ask, how many blitter cycles does it cost? Answer: it will eat 50% of blitter cycles. The A2024 monitor also has a 10hz mode that only ats 25%. I suspect putting the A2024 in mono mode will eat zero. >> I hear its finished, but won't be released until AmigaUNIX v2.0 >>with X11R4 is finished. That way, the 3000UX can run a nice megapixel >>/mega color Xwindows. (the A2410 has a 34010 processor onboard) > >And a fast gfx processor will be needed judging from my experience >with X 8-( That's what the TI34010/34881 is for. The Xwindows code will probably run on the 34010 processor itself instead of the 68030. > > >---------------------------------------------------------------------- >Claus Brod, Am Felsenkeller 2, Things. Take. Time. >D-8772 Marktheidenfeld, Germany (Piet Hein) >csbrod@medusa.informatik.uni-erlangen.de >Claus_Brod@wue.maus.de >---------------------------------------------------------------------- -- / INET:rjc@gnu.ai.mit.edu * // The opinions expressed here do not \ | INET:r_cromwe@upr2.clu.net | \X/ in any way reflect the views of my self.| \ UUCP:uunet!tnc!m0023 * /