Examples of assembly language software you may be familiar with are IBM PC DOS and the spreadsheet program Lotus 1-2-3.

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Those companies were able to clone the IBM PC because IBM made the mistake of allowing its partner, Microsoft, to license a virtually identical version of its PC-DOS operating system to any takers.

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Because different companies use different operating systems, Symbol makes products based on the Palm (nasdaq: PALM - news - people) OS, Microsoft 's (nasdaq: MSFT - news - people) Pocket PC platform, Windows CE and DOS. What these products have in common is their durability.

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Of course if Windows isn't your cup of tea, then you can also install Microsoft's DOS on your Mac using Virtual PC.

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Microsoft developed DOS for IBM, which shipped it with the new PC in August 1981.

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