jay@umd5 (Jay Elvove) (11/04/86)
I really blew it. I tried to do a friend a favor after the store where he purchased a Leading Edge Model D w/hard disk put the wrong version of MS-DOS on his machine. All of his utilities were set to run with version 2.11; the store installed MS-DOS version 3.1 which made it impossible to run many of these programs. I used the SYS command to install the earlier level over the more recent release, which resulted in (according to the store) the complete loss of all data on the hard disk. The symptoms I witnessed were the following: 1) certain interrupt vectors were being zeroed out???, 2) the FDISK command did not recognize the hard disk as belonging to DOS (non-DOS partition, or some such message), 3) DOS (as a result) would not acknowledge the fact that the hard disk was even attached to the system. Does anyone know why installing an earlier version of DOS over a more recent (and, presumably larger) version should cause any problems? I can understand why the converse might be true, since the later levels of DOS tend to grow by leaps and bounds. Please respond via mail. Thanks very much.-- --------------------------------- Jay Elvove jay@umd5.umd.edu c/o Systems, Computer Science Center, U. of MD.
howardl@tekline.UUCP (Howard D. Leadmon) (11/07/86)
In article <1340@umd5>, jay@umd5 (Jay Elvove) writes: > I really blew it. I tried to do a friend a favor after the store where > he purchased a Leading Edge Model D w/hard disk put the wrong version > of MS-DOS on his machine. All of his utilities were set to run with > version 2.11; the store installed MS-DOS version 3.1 which made it > impossible to run many of these programs. I used the SYS command to > install the earlier level over the more recent release, which resulted > in (according to the store) the complete loss of all data on the hard disk. > The symptoms I witnessed were the following: 1) certain interrupt vectors > were being zeroed out???, 2) the FDISK command did not recognize the > hard disk as belonging to DOS (non-DOS partition, or some such message), 3) > DOS (as a result) would not acknowledge the fact that the hard disk was > even attached to the system. Does anyone know why installing an earlier > version of DOS over a more recent (and, presumably larger) version should > cause any problems? I can understand why the converse might be true, since > the later levels of DOS tend to grow by leaps and bounds. Please respond > via mail. Thanks very much.-- I will try and give a very brief reason as to what happend when the DOS version on the drive was 3.1 (this is what it was formatted with) vs the files on the drive (format,fdisk,chkdsk,etc..) were DOS 2.1. One major difference between DOS 2 and DOS 3 is that under DOS 3 the harddisk when it is formatted it allocates the disk clusters in sizes of 2048 bytes, unlike DOS 2 which alocates clusters in sizes of 4096 bytes. The only time that DOS 3 will allocate 4096 byte clusters is when it is a 10meg drive. So what you did was to format the drive with 3.x and have it set the cluster sizes to 2048 bytes, then you reloaded 2.x which believed that a DOS partition wold contain clusters sized at 4096, and that is why you got it telling you that the drive was not a DOS partition. Believe it or not you did not destroy the disk (if there was important data on it), all you would of have to do is to re-SYS the 3.x DOS back onto the harddisk. Instead of installing 2.x back on the drive as the OS, what you should have done was to replace the 2.x commands (format,fdisk,copy,chkdsk,tree,etc..) with the appropriate 3.x commands, this would have solved your problem. One last thing, the reason the 2.x commands would not run was due to the fact that all OS commands have there version included in them, and DOS checks this when it goes to execute the commands. When it noticed that they were not the same it halted execution and gave you a message saying ' Incorrect DOS Version '... I hope this helps you out... -- Sincearley, Howard D. Leadmon Fast Computer Services PATH: ..cp1!tekline!howardl