prindle@NADC.ARPA (Frank Prindle) (01/13/88)
My own experience and that of other members of our user's group shows that the 1571 has an annoying property of failing to properly seat (center on the spindle hub) a diskette about 5% of the time one is inserted. This is curious because the 1571 DOS purposely turns the spindle during disk insertion specifically to help it seat properly! Normally, this is just a minor annoyance - you insert a diskette and try to load a file or directory and the drive does a lot of retries or fails completely. So you just take the disk out and put it in again and generally all is well. Warning: the real problem occurs if the first thing you try to do after insert- ing a diskette is OPEN (for writing) or SAVE! If the diskette is not seated properly, but is able to read the BAM and directory after several retries, it will actually rewrite the BAM, one directory sector, and the file itself OUT OF ALIGNMENT! Subsequent attempts to read this diskette when it is later re-inserted and seated properly will actually have trouble reading the BAM, directory, and the file created because these sectors have been recorded slightly off center. Usually the diskette will be marginally readable and with patience, most of the files can be recovered, especially if you can try it on several drives, but it is still a very annoying situation. The moral is to, whenever possible, take a directory list or load a file from a diskette after it is first inserted to make sure it is seated properly before trying to write to it. This isn't always possible: for example when using a single drive file copy program and it asks you to swap disks often. Flipping the drive lever down more slowly seems to help avoid the problem. Another ploy that seems to help is to insert a diskette, but do not flip the lever down until after the spindle motor stops turning (a few seconds, you can hear it stop). Why this works better beats me. Has anyone else had seating problems with the 1571 and found a solution? Sincerely, Frank Prindle Prindle@NADC.arpa
hedley@cbmvax.UUCP (Hedley Davis) (01/15/88)
In article <8801131406.AA05957@NADC.ARPA> prindle@NADC.ARPA (Frank Prindle) writes: >My own experience and that of other members of our user's group shows that >the 1571 has an annoying property of failing to properly seat (center on the >spindle hub) a diskette about 5% of the time one is inserted. This is curious >because the 1571 DOS purposely turns the spindle during disk insertion >specifically to help it seat properly! Normally, this is just a minor >annoyance - you insert a diskette and try to load a file or directory and the >drive does a lot of retries or fails completely. So you just take the disk >out and put it in again and generally all is well. > Gee, works ok for us. Of course, Fred and I both have a curious habit of inserting the disk, closing the lever, and then wiggling the disk back and forth a couple of times in the drive. Hedley