Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!think.com!rpi!batcomputer!cornell!vax5.cit.cornell.edu!n65j From: n65j@vax5.cit.cornell.edu Newsgroups: comp.sys.ibm.pc.hardware Subject: Re: Simple Cache Question Message-ID: <1991Jun6.182157.5306@vax5.cit.cornell.edu> Date: 6 Jun 91 22:21:57 GMT References: Distribution: comp Organization: CIT, Cornell University Lines: 43 In article , chau@caen.engin.umich.edu (Hin Fai Chau) writes: > This has long been a question in my mind. Can anyone please > tell me whether I still need to install FASTOPEN and SMARTDRV > or other disk cache programs such as HYPERDISK if I have > already had a 32 K cache buffer in my disk controller card Depending on the type of software you are using you can still see major performance gains from the additional disk cache software. 32K is a very small cache to hold repeatedly-accessed data such as the file allocation table and directory data, let alone any of your own files that might be repeatedly accessed during something like a database search or the compile of a large multimodule program. If your main use is for small spreadsheets, however, you wouldn't be using the drive much in the first place and even the controller cache would be underused. This is only the tip of the iceberg of explanation, but the bottom line is probably that the software cache could very well improve your system's performance if your computer uses now involve repeated reading of the same directories or files at short intervals. > and another 64 K in my 386 processor? This caches the transfers of data between the microprocessor and the main memory, so it does not have anything directly to do with the controller or software disk cache. > Does a software disk cache program actually create extra > overheading if I have already got a hardware one? It again depends on how your application software makes use of the disk. Let me suggest an empirical test that sold me on disk cacheing. Get Hyperdisk from a BBS or a FTP site like SIMTEL or WUARCHIVE, and try it. Since it is shareware, you don't have to pay to try it out. When I first started using a cache, I had been bothered by extensive disk activity (head seeking) during Turbo Pascal compiles. Many small files had to be accessed repeatedly, and it seemed to take forever to compile some multi-module programs. I installed a cache (PC-CACHE which comes with Central Point's PC Tools) and the drive became practically silent as the compiler had only to refer to the cached copy of the many small files after the first time, instead of having to wait while the heads zipped all over the place. I saw similar results with dBase III, which often uses a lot of files, repeatedly. -- regards, Steve Pacenka, Cornell U.