Long-term Memory

I just read an interesting article on how HFS+ deals with fragmentation. Not only will it take proactive steps to avoid fragmentation, apparently it will defragment some files on-the-fly.

This forensics-site has a very detailed article on the hex-dumps you can get from an HFS+ partition.

Everyone with some basic knowledge on the TCP/IP protocol knows that TCP can cope with lost packets. The lost packet is retransmitted, the send-rate is throttled back a bit and on it goes. I just found this usenet-post by stanislav shalunov giving a formula to calculate just how much bandwidth remains after all that “throttling back”:

Standard TCP has throughput that’s limited by approximately MSS/(RTT*sqrt(loss)). Therefore, if your MSS is 1460B and RTT 70ms (typical for a cross-continent path), you need no more no more than 0.0003% packet loss to get 100Mb/s or 0.03% to get 10Mb/s. Note that, because of that square root, every doubling of required throughput means dividing permissible packet loss by four.

Recently Bruce Schneier has posted some very good and readable posts on biometrics and impersonation, explaining the difficulties with security systems. Recommended reading for everyone in security!

Recently I got a PowerBall. Needless to say, I wanted to know exactly how this thing works. Although the Wikipedia article gives some descritption, I found this post on Usenet (local copy) that goes into the dirty details of formulla’s.