Linux is now second only to NT in server market unit sales, according to IDC. The open source OS accounted for 25 per cent of all shipments in 1999, zooming up from 16 per cent the previous year and hopping past Unix and NetWare on the way. NT's share meanwhile was static at 38 per cent, while Unix and NetWare both fell away. With the exception of Linux, which is undoubtedly on the way up a lot faster than analysts had expected, the picture isn't entirely clear. NT's lack of growth can be put down to Y2K and waiting for Win2k to some extent, but it also suggests that Microsoft's attempts to leverage NT into the enterprise may be stalling. As far as the others are concerned, one might at first glance think that Novell and the Unix vendors would be hurting, but share of new shipments and of installed base are two separate things. Novell still has a substantial cushion of NetWare shops, while Unix sales still comfortably account for more than half of total revenues on server software. On top of that, increased Linux sales are a lot more likely to help the Unix outfits' service revenues than Microsoft's, so they're unlikely to be entirely displeased. IDC's picture of the client market isn't quite the one of impending triumph for Linux portrayeed by the server stats, but it's still promising. At 4 per cent of sales it's only a little behind MacOS, and bearing in mind that nobody much has been really trying to sell Linux as a client OS yet, this isn't a bad start. NT had 21 per cent of client sales, and other Microsoft (largely Win 9x) 66 per cent. Linux sales revenues overall were of course stupidly low, but perhaps that indicates that measuring success by new shipments is becoming a somewhat artificial exercise. All of the major vendors, including Microsoft, are now pursuing services revenues, so although they need new shipments to keep their markets topped up, what's really important to them is the total number of customers they've got out there, and how much they can make from them. ®