SELECT was introduced in IBM PC DOS 3.0, along with internationalisation support, and made available in MS-DOS starting with version 3.3.
Its purpose is to create a bootable disk with support for a given country code and keyboard layout. The syntax, starting with version 3.2, is
SELECT [[drive1:] drive2:[path]] country keyboard
drive1 is the source drive (
A by default),
drive2 the destination drive (
B by default),
country is one of the supported country codes (033 for France, 049 for Germany — West Germany at the time — etc.), and
keyboard is one of the available keyboards (
This was effectively the installation procedure for floppy-based versions of DOS, outside the US: prepare a blank floppy, boot with DOS disk 1, and run
SELECT with the appropriate country and keyboard code. This would result in a usable DOS disk, with all the contents of DOS disk 1, and a correctly-configured keyboard as soon as the system was booted.
Version 3.0 and 3.1 of
DISKCOPY to copy the source disk to the destination disk, formatting the latter if necessary. Version 3.2 and 3.3 use
XCOPY instead; version 3.3 supports hard drives (although running
FDISK is left as an exercise for the user, before running
SELECT). In both cases, the destination disk is erased, and all the contents of the source disk are copied, not only the files required to support the desired country and keyboard. In version 3.2, if the source disk doesn’t include the
KEYBxx file required for the desired keyboard, the user is prompted to instead the disk containing it. All versions then write an appropriate
AUTOEXEC.BAT to the target disk, containing respectively
COUNTRY.SYS path too if necessary), and
The default path (
PATH above) depends on the installation path (the second parameter).
In version 4.0 of PC DOS and MS-DOS,
SELECT became an interactive installation tool, which was started automatically from the installation disk (or the “Select” disk on 5.25” disk sets).
In version 5.0 of PC DOS and MS-DOS, the setup program was renamed to
SETUP.EXE and introduced support for upgrading DOS. This is where
DELOLDOS comes from: when upgrading,
SETUP would create
DELOLDOS, which could be used to undo the upgrade, restoring the previous version of DOS (and its boot sector etc.).
There appears to have been another version of
SELECT, written by Karl D. Wright for Phoenix Technologies, and included in at least some OEM versions of MS-DOS 3.2; a quick look through it suggests it does the same thing as the “official”
According to The MS-DOS Encyclopedia,
SELECT was available in PC DOS 2.0, but my PC DOS 2 disks don’t have it and there wouldn’t have been much use for it on PC DOS 2 which didn’t have either the
COUNTRY statement or the
SELECTcommand that some may have enjoyed with 4DOS, of course. (-: