hsc@mtuxo.UUCP (h.cohen) (06/28/86)
I have deleted the author's name to avoid personal interruptions to the author. *** Process with tbl, nroff/troff and mm macros*** .ND "June 19, 1986" .TL Living with a mix of 1.2-MB and 360-KB floppy drives .AU .MT 0 Here is a summary of how to live with a mix of 360-KB and 1.2-MB floppy drives on MS-DOS machines. "Getting Started with Your AT&T Personal Computer 6300 PLUS" says (page 3-36) .DS I F 5 "... if you must use a 360-KB diskette in the 1.2-MB drive (drive A), use it only for reading information. After using the 1.2-MB drive to write on a 360-KB diskette, the diskette can only be used in 1.2-MB drives." .DE AT&T does not officially support writing a 360-KB diskette in a 1.2-MB drive and then reading it in a 360-KB drive. Many people find that it can be done with reasonable reliability, though, subject to the guidelines given below. These guidelines are for informational purposes only, and AT&T takes no responsibility for operations not supported in PC6300 PLUS user documentation. .P The 360-KB head is wider than the 1.2-MB head, so a 360-KB head reading a track that has been written by a 360-KB drive first and a 1.2-MB drive last will be reading a narrow track of new data in the middle of a wider track of old garbage. Therefore: .P 1.2-MB drives will normally read 360-KB diskettes with no trouble, whether the diskettes were formatted and/or written on a 360-KB drive or a 1.2-MB drive. .P 360-KB drives will normally read 360-KB diskettes that have been formatted only on a 1.2-MB drive and written only on a 1.2-MB drive. .P 360-KB drives may have trouble reading diskettes that have been formatted and/or written first on a 360-KB drive and then on a 1.2-MB drive. If you are reading a floppy and get an error message with "ABORT, RETRY, OR IGNORE," either abort or retry. "IGNORE" defeats the error-checking mechanism and can sprinkle garbage amidst your data. As long as you don't "IGNORE", it does not hurt to try reading. For best results, though, use VIRGIN or BULK ERASED diskettes to take data from a 1.2-MB drive to a 360-KB drive. It helps to use higher-than-minimum quality (i.e., 96tpi certified rather than 48tpi certified) diskettes, too. Format and write the diskettes only on 1.2-MB drives. In short, the user should keep two types of 360-KB diskettes in a mixed-drive environment: .DS .TS c s c s l l l l. Type 1 Type 2 Format and Read Format and Read Write On On Write On On 1.2-MB only 1.2-MB 360-KB only 1.2-MB or or 360-KB 360-KB .TE .DE .P Microbridge Computers Int'l., Inc., 655 Sky Way, Suite 125, San Carlos, CA 94070, (415)593-8777, sells an MS-DOS program called "CPYAT2PC," which is supposed to let a 1.2-MB drive write a 360-KB diskette that is always readable on a 360-KB drive, even if it has been written by a 360-KB drive at some time in the past. AT&T has not tested this program and has no official or unofficial opinion on it. I would be interested in hearing about customer experiences. .SG