1. Is 64 bit computing ready for the desktop?
a.k.a. The Story of Me and My Laptop
David North

2. Can represent integers roughly from 2-64 to 264
What is 64 bit?
CPU capable of dealing with 64-digit binary numbers (as opposed to 32 bit, last 15 years)
Can represent integers roughly from 2-64 to 264

3. Why should I care? Breaking 4 GB memory barrier
64 bit addresses allow us to support memory up to 16.8 million TB
(realistically, physical limitations currently mean 32GB is the top)

4. Other advantages
Memory-mapped files for faster disk access – 4gb DVD images, etc
Security: fewer, if any, viruses and exploits for 64 bit platforms

5. Lack of application availability, esp for 64 bit Windows
The downsides
Lack of application availability, esp for 64 bit Windows
Lack of device drivers
Same data takes up more space in memory than on 32-bit (swollen pointers, alignment padding)
Hence increased mem reqs of a process => implications for processor cache efficiency

6. What's out there?
AMD were first to make a mass-marked 64 bit architecture for desktops/laptops: the AMD64, used in some Athlon and Opterons, and later the Turion
Intel eventually followed with the EM64T, used in the latest Pentiums and Xeons

7. A case study: me and my laptop
[on the server: 64 bit is go, has been for over a year]
Bought a 64 bit laptop (with AMD64 processor) in June 2006
It came with 32 bit Windows XP
Should I install a 64 bit OS?
64 bit Windows: sheer lack of software, expensive
64 bit Linux!

8. March 2007: Ubuntu 64 Sheer lack of packages in the repositories
Flash, Realplayer totally borken
Not much help in the forums, because nobody was using it
Fail. Back to 32 bit.

9. April 2008: Try again
Much better: nearly every package you can think of is there
Flash, Realplayer took some hacking, but were doable
Not much difference in speed from 32 bit, day-to- day
Fixed some driver issues, introduced others

10. This isn't a problem for most people...
Downsides?
Compilers/interpreters may now use 64bit integers, which could mess up some programs, e.g. The Oberon Compiler
This isn't a problem for most people...

11. Conclusion

12. Questions?