Microsoft was selected as the vendor
os for IBM
DOS, which stands for Disk Operating System.
ibm
The original operating system for an IBM PC with Intel Processor was DOS (disk operating system) which operated at a command level prompt of C:
windows NT
hi
os/2
ibm
Microsoft
Win98
IBM System z servers are supported by a multitude of operating systems, such as z/OS, z/VSE, z/TPF, Linux on System z and the z/VM hypervisor.
The first simple "operating system" was a program called IBSYS that IBM released for the IBM 7090 transistorized computer in 1960. IBSYS was derived from a program IBM's customer General Motors had written for their IBM 701 and IBM 704 computers and contributed to the IBM computer users group SHARE. SHARE had rewritten General Motor's original program, calling it SHARE Operating System for the IBM 704 and IBM 709 which was the version adapted by IBM to make IBSYS. IBSYS was not like modern operating systems however and would now be called a batch monitor program..