Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!rutgers!ucsd!ucbvax!decwrl!pyramid!prls!philabs!micomvax!ray From: ray@micomvax.UUCP (Ray Dunn) Newsgroups: comp.sys.ibm.pc Subject: Re: 1.2MB drive Message-ID: <1171@micomvax.UUCP> Date: 6 Jul 88 21:01:00 GMT References: <8362@bellcore.bellcore.com> Reply-To: ray@micomvax.UUCP (Ray Dunn) Organization: Philips Electronics Ltd. (TDS - Montreal) St. Laurent QC, Canada Lines: 70 In article <8362@bellcore.bellcore.com> jef@djinn.UUCP (Jonathan E. Flamm) writes: >I know that there are problems with diskettes written on 1.2MB drives >when they are read on 360KB drives ( I believe it has to do with only >1/2 of the track being written due to the narrow track width). Is there >software available that will RELIABLY write 360K diskettes on 1.2MB drives >so they can be reliable read on 360K drives. There is no *RELIABLE* way of doing this. The problem is not with software it is with physics. There have been several replies saying: "Brand X seems to work fine", "I have had good luck with...". Please note that this is *INDEED* a question of luck, and a factor of *both* the 1.2 Meg drive you are writing on, *and* the 360K drive you are reading from, *and* the quality of the media you are using. There is probably a higher correlation between particular *samples* of drives than between particular manufacturers of drives. It is indeed true that you increase your chances of success if you format the disks on a 360K drive. >I know that there is no problem with the new 3 1/2 1.44MB and 720K formats. Unfortunately, this is not totally correct, the problems are just a little more devious! The early IBM PS/2 machines showed serious interchangeability problems, and many clone PC's with 3.5 inch drives still do. Lack of a full specification standard for 1.4Meg drives is part of the problem, and again, physics comes into play! In particular, look for the following problem: Diskettes formatted on a 720K drive and overwritten on a 1.44 Meg drive (at 720K density) are often then unreadable on a 720K drive. The severity of the problem varies very distinctly from drive manufacturer to manufacturer, and from sample to sample. It appears to be rare on *current* IBM PS/2 machines. There are significant interchangeability problems from manufacturer to manufacturer with 1.4Meg diskettes. Don't rely on being able to carry a 1.4Meg diskette from your machine to one of a different make! The fact that early 3.5 inch drives (and some current ones) did not check the media has caused some grief. This allows a diskette to be formatted at the wrong density, i.e. allows a 720K diskette to be formatted as 1.4Meg, or, just as bad, 1.4Meg as 720K. Unfortunately, I am not at liberty to identify the worst offenders in the interchangeability game!! The above is fact, the following is opinion. I don't have the info at my fingertips, but I believe some IBM PS/2 machines may still not lock out illogical format attempts correctly. As clone manufacturers, we have spent much time and effort identifying and overcoming these problems. Disclaimer: The above should be taken as personal opinion of the writer, may not reflect that of Philips Electronics Ltd., and is given for information purposes only. -- Ray Dunn. | UUCP: ..!{philabs, mnetor}!micomvax!ray Philips Electronics Ltd. | TEL : (514) 744-8200 Ext: 2347 600 Dr Frederik Philips Blvd | FAX : (514) 744-6455 St Laurent. Quebec. H4M 2S9 | TLX : 05-824090