There was also a DOS 1.05 released between 1.00 and 1.10 that fixed a math bug in BASIC, if I recall correctly. It was available from retailers but it was never sold as a packaged item. I've got a copy of it, obtained from ComputerLand, in my DOS 1.0 box. I'm pretty sure it boots as DOS 1.0 but contains new BASIC and BASICA programs. Erik Klein www.vintage-computer.com www.vintage-computer.com/vcforum The Vintage Computer Forum Fred Cisin <cisin at xenosoft.com> wrote: On Wed, 4 May 2005, Eric Smith wrote: Eric is right, of course, but IBM (and particularly some third party IBM dealers, such as Computerland) also liked to bundle a few products together. Since low level format of hard drives was only available in the "Advanced Diagnostics", if you bought a machine and OS at the same time, IBM would gladly "install" it. PC-DOS 1.00 was released simultaneously with the 5150. (8/11/1981) PC-DOS 1.10 added support for double sided drives. PC-DOS 2.00 was released simultaneously with the availability of the XT, and added support for 9 sectors per track (v 8), subdirectories, and hard drives. PC-DOS 2.10 was released simultaneously with the PCJr and "portable PC", and slowed down disk access for the lousy Qume 142 drives PC-DOS 3.00 was released simultaneously with the AT, and added support for 1.2M floppies. PC-DOS 3.10 added the network redirector and a few other items. PC-DOS 3.20 added support for 720K 3.5" drives. PC-DOS 3.30 was released simultaneously with the PS/2s, and added support for 1.4M drives. PC-DOS 4.00 added support for hard drives > 32M PC-DOS 5.00 add some bundled software PC-DOS 6.10 added bundled Compression. PC-DOS 7.00 is too new to worry about. NOTE: 1.25, 2.11, and 3.31 were only available as MS-DOS, NOT PC-DOS. -- Grumpy Ol' Fred cisin at xenosoft.com