Did you know that Microsoft is neither the largest software company by sales or by product line? It’s really IBM.
Microsoft offers two operating systems, a database server, an e-mail server and a webserver, an office suite, plus a few others.
IBM offers no less than four operating systems (z/OS, OS/2, AS/400 OS and AIX, plus a few others), a database server, an e-mail server, two webservers, an office suite, an instant messaging program and a few others.
In fact, even Sun Microsystems offers a larger product line than Microsoft, with many programs not available from either Microsoft or IBM.