![]() Therefore Apple introduced the “blind” operations. Because of this, the only really safe way to do the I/O is to poll the SCSI chip for the arrival of a new byte each time you need one. When transferring data to or from a SCSI device, there is no support for hardware handshake on the Mac Plus (there is some on the other Macintoshes). In the following discussion we will talk about read operations only, but the discussion applies just as well to write operations. ![]() The reason that the performance of these operations can be enhanced is that Apple’s code to do these operations is (and must be) suited to handle a variety of disk types. The accelerator works only on a Mac Plus! It enhances the throughput of I/O operations for so called blind read and write operations. GEnie E-Mail address: “C.Magendanz” From Accelerator.doc, dated JWHAT SCSI-ACCELERATOR IS ALL ABOUT. Make sure to read the “SCSI Accelerator.doc” file to find out how the INIT works, how to install it, and for whom it will be useful. I ask Dolf’s forgiveness for tampering with his work, but without the INIT installed, I found my Mac Plus operating at almost 1/8th of its enhanced speed. In all other ways, the INIT is untouched. I have updated the INIT to work with System 6.0.x and System 7.0. System 7.0 has left the actual SCSI Manager implemented as a user trap, but relatively untouched in content. In the process, he also added an icon to the INIT, which is only shown when the patch is actually applied. Thus, the INIT was fixed to check for both cases and handle them correctly. With some hacking he found that the patch was still applicable, but that it had to be applied at a different position in the SCSI Manager code. The reason was that the code checked the System’s SCSI Manager code for the occurrence of certain instructions so that it could be sure that it was patching the right thing in the right place. With the arrival of System 6.0.x a Dutchman by the name of Dolf Starreveld found that the INIT no longer installed the patch. However, a few unfortunate but daring individuals quickly discovered that the original INIT was plagued with a nasty bug that lead to much frustration, but inevitably to a quick bug fix that remedied the problem. Many years ago, someone left an INIT on the net that was reported to improve SCSI disk performance considerably. From the Read Me file, dated June 3, 1991 If you are using System 6.0.8 or earlier, you want to get SCSI Accelerator 2.1. And you may also want to join our System 7 Forum. It’s been a few years, but I believe I had my hard drive interleaved at 2:1 before I put a Brainstorm accelerator in my Mac Plus, 1:1 after that. (In the olden days, before hard drives had buffers, you had to interleave the data sectors in such a way that they didn’t overwhelm the computer’s data bus.)ĭownload SCSI Accelerator 7.0 only if you are using System 7.0 through 7.5.5 on a Mac Plus. As a former Mac Plus owner, I will attest to the fact that they really do work. It is available in Catalan, Croatian, Czech, Danish, Dutch, English, Finnish, French, German, Greek, Hungarian, Italian, Japanese, Korean, Latvian, Norwegian, Polish, Portuguese, Romanian, Russian, Simplified Chinese, Slovenian, Spanish, Swedish, Traditional Chinese, Turkish and many other languages.SCSI Accelerator 7.0 is a set of extensions that work with a Mac Plus running System 7 and allows improved SCSI throughput. It is absolutely not harmful at all for you Mac and your Applications, since it does not modify anything on your Mac but just optimizes its processing power, only when the application is running. It doesn't need any installation which makes it very easy to use. It appears in the right side of the menu bar. It tells the Process Manager of the UNIX layer of Mac OS X to always assign the maximum priority to the foreground application. You can set the percentage of acceleration between 0% and 100%. It redirects unused processing power of your CPU to the foreground application. It automatically detects the foreground application you are using. It can increase by up to 30% the power of your Mac. CPU Speed Accelerator allows you to drastically increase the CPU allocated to your foreground applications to make the most of the power of your Mac. You want to increase the power of your Mac? At very low cost? You want to increase by 20% to 30% the speed of your applications without spending money in new hardware? You want to automatically always make the most of the power of your CPU to the foreground application you are using? Then CPU Speed Accelerator is what you need.
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