Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!evax!cs4344af From: cs4344af@evax.arl.utexas.edu (Fuzzy Fox) Newsgroups: comp.sys.cbm Subject: Re: Fastloads vs. JiffyDOS Message-ID: <1991Jan2.224325.26324@evax.arl.utexas.edu> Date: 2 Jan 91 22:43:25 GMT References: <1991Jan1.165812.10735@jarvis.csri.toronto.edu> <1991Jan2.030900.8433@evax.arl.utexas.edu> <1991Jan2.144725.17549@jarvis.csri.toronto.edu> Organization: Computer Science Engineering Univ. of Texas at Arlington Lines: 43 In article <1991Jan2.144725.17549@jarvis.csri.toronto.edu> leblanc@eecg.toronto.edu (Marcel LeBlanc) writes: >Agreed again, but the figure of '10-15 times' speedup with JDOS is only with >an optimal interleave. If you try to LOAD a large program that has been >saved at the standard 1541 interleave of 10 sectors, you'll get about the >same speed up as Epyx FastLoad gives you, which is about 5-5.5 times. Good point, something I neglected to mention. This is a case where your file copier can make a difference. (Of course everyone out there is using Maverick, aren't you?) A save skew of 10 will give you approx. 5x speedup; a skew of 6 will give you a speedup of 7-10x (guessing); and a skew of 4 will give you about 15x speedup, but only on a 1571. 1581 drives do not have problems with sector skewing, since they buffer whole tracks at a time. You will find a tremendous boost of performance if you use a filecopier to copy files to a new disk, and use an optimum interleave. JDOS automatically saves files in the 'best' interleave, so simply loading a program and saving it again will often give the same results. On a side note, be aware that the loading method also affects load time, as with SEQ files. SEQ, USR, and REL files are saved by JDOS with an interleave of 10, so that they will load at the fastest rate possible, about 5x speedup. PRG files are saved at the optimum interleave for the drive you save them on. 1541 drives will save PRG's at a skew of 6, while 1571 drives will save at a skew of 4. So you can see that a 1541 will load at about 7-10x, while a 1571 will load at 15x. This is a side benefit of using a 1571, and also be aware that JDOS always uses double sided mode on 1571's, so you can use double-sided disks, even when the drive is in the so-called 1541 mode (ie, U0>M0). Note that a 1541 even with JDOS cannot read sectors with a skew of 4 at optimum speed. So a file saved with JDOS on a 1571 will load slower than normal if a 1541 is used to load it back. >Just for kicks, LOAD the same file with your SS V5. This is my favorite SS feature, the fact that a file can load at optimum speed regardles of save skew. Kudos! -- begin 644 .signature G5&AI