Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!TAURUS.BITNET!finkel From: finkel@TAURUS.BITNET Newsgroups: comp.sys.cbm Subject: Re: turbodisk and IEEE Message-ID: <8902160843.AA11442@MATH.Tau.Ac.IL> Date: 16 Feb 89 08:43:32 GMT Sender: daemon@ucbvax.BERKELEY.EDU Reply-To: Lines: 85 >Subject: Re: turbodisk and IEEE >Summary: Non-standard formats can give much better speed WITH 1541 >Keywords: turbo, non-standard sectors >Message-ID: <89Feb14.155723est.2717@godzilla.eecg.toronto.edu> >Date: 14 Feb 89 20:45:50 GMT >References: <8902130828.AA09474@MATH.Tau.Ac.IL> >Organization: EECG, University of Toronto >Lines: 31 > >In article <8902130828.AA09474@MATH.Tau.Ac.IL> >There has been lately a talk about IEEE drives, and their owner's dislike >>of turbo disk programs. >> >>Well, I have written a turbo program for 8050/8250/SFD1001. It uses all 3 >>processors ( 2 in the drive, 1 in the C64 ) so it can easily read a full >>track at a time with zero interleave. The program reads the disk using a >>nonstandard file format ( that coexist on the same disk with normal PRG/SEQ >>file ) that uses 256 data bytes per block and continous block allocation on >>the disk. I have a special copy program that prepares such disks. The program >>runs on special IEEE cards manufactured by the company on which I work. (these >>are actually network cards. up to 20 C64's can share the same IEEE drvice ). >>Speed is much faster than anything possible with any C64.. I think it's faster > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ not true! >>than the C128 burst mode. I also have a C128 version of the program. > >It should be faster than the C128 burst mode, because of the greatly reduced >overhead required in decoding non-standard sectors! This isn't something >unique to IEEE drives, of course. The _STANDARD_ 1541 fast loader on Super >Snapshot V4 is FASTER than a 1571/C128 in burst mode (12-15x speedup), and >about the same speed as a 1581/C128 in burst mode. Supplied on the utility >disk, is a translator program which converts to Turbo 25 format. This is a >non-standard format such as the one you described. As the name implies, it >achieves 20-25x times speedup over standard 1541. This is for the C64, and >is MUCH faster that C128 burst load. Well, you didn't understand me. it seems that I was too conservative.. a. My Turbo is 50% faster than any THEORETHICAL 1541 speedup! my drives reads a 8250 track that contains 27 sectors in one revolution! the 1541 has only up to 20 sectors on a track. even if you will have such a full-track-reader-in-one-revolution for the 1541 ( which I doubt ), your turbo will STILL be 50% slower! b. My turbo uses STANDARD 8250 sector format! it's the DOS format that isn't compatible, not the sector format! you can read these sectors using U1:, U2:, and you can do D0=1 as much as you like. the ONLY thing you can't do on such a disk is (1) to validate it (b) to copy files using the internal copy command. I don't have a copy program for such files. What we do is to have a 'normal' copy of the files, and when we finish working on the file, we copy it to the 'fast' format. there is also anotehr limitation to the copy program. I don't think it will work with the SFD1001. it must use a double-drive unit. c. I think it will not be hard to modify my turbo to accomodate the standard DOS format, and then find teh equivelent M-W on the 8250/8050 to change the interleave ( as on the 1541 ), and record disks with interleave 1. to demonstarate the speed of it, lets say that loading a picture from within Doodle, it takes about 1 second, once you see the computer starts drawing it. ( i.e. not including the directory search time, and the time required to seek to the appropriate track ). we had a demo disk ( made before I wrote the 'file' structure ), that recorded a series of doodle pictures on the disk's tracks, and a demo code that read them right of the disk's surface at predefined tracks. the avarage time between a screen change ( the demo read 8-10 pictures right after another, then restarted at the beginning ), was about 1 second. ( remember - no directory search, and the disk is aleady spinning at full speed ). We almost don't use it any longer - actually we almost stopped selling C64/128 networks. besides, our IEEE based HD server is even faster, has a true 'fast' file structure, and can do real 'fast save'. > >Marcel A. LeBlanc | University of Toronto -- Toronto, Canada >leblanc@eecg.toronto.edu | also: LMS Technologies Ltd, Fredericton, NB, Canada >------------------------------------------------------------------------------- >UUCP: uunet!utai!eecg!leblanc BITNET: leblanc@eecg.utoronto (may work) >ARPA: leblanc%eecg.toronto.edu@relay.cs.net CDNNET: <...>.toronto.cdn > ------------------------------------------------------------------------------- Udi Finkelstein | Bitnet: finkel@taurus.bitnet or finkel@math.tau.ac.il Tel Aviv University | Internet: finkel%taurus.bitnet@cunyvm.cuny.edu Israel | UUCP: ...!psuvax1!taurus.bitnet!finkel -------------------------------------------------------------------------------