markz@microsoft.UUCP (Mark Zbikowski) (01/17/84)
What is the difference between DOS 2.0 and DOS 2.1?. The differences are as follows: Support for PCJr's half-height diskettes. These require a greater head settle time than did the previous full size-floppies. Unfortunately, there is no way to tell the half-highs from the full sized ones so every IBM diskette now has the slower head settle. This slower head settle is only applied to seek/write combinations and seek/verify combinations. It is still slow. Support for the PCJr's ROM. This consists of looking up a command in the ROM tables and then setting up an EXEC for it. Bug fix 1: IOCTL control read/write used to perform a media-check sequence before issuing the command to block devices. The function no longer issues the media-check sequence. Bug fix 2: Due to the strangeness of having one system call (exec) being loaded as part of COMMAND, there was a segment register foulup that resulted in locations 2Eh through 31h being trashed in the data segment at the time of the exec system call. This problem was fixed.