Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: Notesfiles; site uokvax.UUCP Path: utzoo!watmath!clyde!floyd!vax135!houxz!houxm!ihnp4!inuxc!pur-ee!uiucdcs!uokvax!emjhm From: emjhm@uokvax.UUCP Newsgroups: net.micro Subject: Re: Floppy disk information request - (nf) Message-ID: <3400044@uokvax.UUCP> Date: Sun, 17-Jun-84 13:53:00 EDT Article-I.D.: uokvax.3400044 Posted: Sun Jun 17 13:53:00 1984 Date-Received: Thu, 21-Jun-84 06:08:19 EDT References: <9102@lanl-a.UUCP> Lines: 38 Nf-ID: #R:lanl-a:-910200:uokvax:3400044:000:2638 Nf-From: uokvax!emjhm Jun 17 12:53:00 1984 #R:lanl-a:-910200:uokvax:3400044:000:2638 uokvax!emjhm Jun 17 12:53:00 1984 Double Density Single Sided disketts are manufactured form the same double sided oxide coated Mylar ribbon. Some manufacturers coat the oxide layer with a non abrasive lubricant to reduce head wear which is more critical on double sided (ie two heads) because of the hard surface on either side of the diskette. In other words, a DDSS diskette usually means that it has been lot screened and certified to have no dropouts on one side. It doesn't mean that the other side is not just as good but rather that it has not been certified. Of course the lot screening doesn't guarantee that the certified side is good either but the company that sells the didssketteses has guaranteed that if you find a bad one, you can get it replaced. Now as for making a flippy diskette. Most disketts are not really made properly to spin backwards. If you punch an index hole and write protect hole in the jacket so that you can put the disk in upside down and record on the other side of a singleon a single sided drive, this could cause the wiping action of the fabric inside the jacket to release some of the oxide that it has been cleaning from the diskette surface. When this happens, you take the chanced of getting some of this loose oxide picked up on the head and cuausing dirty heads which can destroy disketts and decrease the life of the heads. On a single sided drive, the soft pad opposite the disk head can also pick up some of the devrisbris and there is no effective way to clean it so you have to partially dismantle the drive and replace the pad if it gets dirty. If you use a diskette which has both sides poillished and coated with a silicone surface like scothScotch or Datalife Verbatim, you will probably have no problems. Even though it's probably not recommendsesd to use both sides of a diskette, most people who have sidngle sided drives punch the holes in the jacket and end up with twoice the capacity and have relatively few problems despite the analytical rpoblemsproblems mentioned. By the way, they used to manufacture foloppy disk drives which had two sets of photocells for the index and write rprotect sensors so that you could use both sides of a floppy diskette without punching the holes in the jackett I havent't heard of these kinds of drives mentioned for quite a qhilewhile. I'm not sure that it was because of problems like those mentioned before or that the extra expense could probably but you a double sided drive uy you a double sided drive in which case thae dual photocells were not needed. Hope this helps...