Tim Daneliuk <[EMAIL PROTECTED]> writes: > I worked for an Airline computer reservation system (CRS) for almost a > decade. There is nothing about today's laptops that remotely comes close > to the power of those CRS systems, even the old ones. CRS systems are > optimized for extremely high performance I/O and use an operating system > (TPF) specifically designed for high-performance transaction processing.
Yeah, I've been interested for a while in learning a little bit about how TPF worked. Does Gray's book that you mention say much about it? I think that the raw hardware of today's laptops dwarfs the old big iron. An S/360 channel controller may have basically been a mainframe in its own right, but even a mainframe in those days was just a few MIPS. The i/o systems and memory are lots faster too, though not by nearly the ratio by which storage capacity and cpu speed have increased. E.g., a laptop disk these days has around 10 msec latency and 20 MB/sec native transfer speed, vs 50+ msec and a few MB/sec for a 3330-level drive (does that sound about right?. > Web servers are very sessions oriented: make a connection-pass the > unit of work-drop the connection. This is inherently slow (and not > how high performance TP is done). Moreover, really high perfomance > requires a very fine level of I/O tuning on the server - at the CRS > I worked for, they performance people actually only populated part > of the hard drives to minimize head seeks. Today I think most seeks can be eliminated by just using ram or SSD (solid state disks) instead of rotating disks. But yeah, you wouldn't do that on a laptop. > For a good overview of TP design, see Jim Gray's book, "Transaction > Processing: Concepts and Techniques". Thanks, I'll look for this book. Gray of course is one of the all-time database gurus and that book is probably something every serious nerd should read. I've probably been a bad boy just for having not gotten around to it years ago. > P.S. AFAIK the first CRS systems of any note came into being in the 1970s not > the 1960s, but I may be incorrect in the matter. >From <http://en.wikipedia.org/wiki/Sabre_%28computer_system%29>: The system [SABRE] was created by American Airlines and IBM in the 1950s, after AA president C. R. Smith sat next to an IBM sales representative on a transcontinental flight in 1953. Sabre's first mainframe in Briarcliff Manor, New York went online in 1960. By 1964, Sabre was the largest private data processing system in the world. Its mainframe was moved to an underground location in Tulsa, Oklahoma in 1972. Originally used only by American, the system was expanded to travel agents in 1976. It is currently used by a number of companies, including Eurostar, SNCF, and US Airways. The Travelocity website is owned by Sabre and serves as a consumer interface to the system. -- http://mail.python.org/mailman/listinfo/python-list
