MS-DOS 1.25 [Seattle Computer Products OEM with Tarbell FDC]
Released 1982 by Seattle Computer Products
For SCP S-100 "Gazelle" with Tarbell (not Comemco) controller

This is a Seattle Computer Products OEM version of MS-DOS 1.25 for
the 8086 SCP Gazelle with a Tarbell Disk Controller.

This archive contains the original setup disk, and a work disk in
ImageDisk format. The images are for 250k 8-inch floppy disk media
(77 tracks, 1 head, 26 sectors per track, 128 bytes per sector FM)

It also includes Basic-86 Rev 5.21 11-nov-81 and Perfect Writer (must
be configured first).

Important: These disks are NOT for IBM PC compatible hardware or IBM
PC emulators.

Source: http://bitsavers.trailing-edge.com/bits/SeattleComputer/

Note that the Altair emulator does not emulate Tarbell controllers. 
