Igor's Computer Blog

Today, I had lunch with the mother of the internet . Among other things she told me her poem that accompanied the spanning tree protocol . Perhaps if a poem was required for each algorithom and protocol submission,  computer science would be simple and clear. With great pleasure I reproduce Radia's poem: AlgoRhyme I think that I shall never see a graph more lovely than a tree. A tree whose crucial property is loop-free connectivity. A tree that must be sure to span so packet can reach every LAN. First, the root must be selected. By ID, it is elected. Least-cost paths from root are traced. In the tree, these paths are placed. A mesh is made by folks like me, then bridges find a spanning tree. Radia Perlman

As a younger man I remember arguing with a co-worker about the death of local storage.  Me: Who wants to store data themselves?  I can store all data in the cloud, where it will be preserved forever! Wiser co-worker: What incentive does this cloud have to keep your data? I'll keep my data on my local hard drive thank you very much!   8 years later my co-worker was  correct. I got the following letter from Google today: Later this month, hosted video content on Google Video will no longer be available for playback. <snip> We’ve added a Download button to the video status page, so you can download any video content you want to save. If you don’t want to download your content, you don’t need to do anything. (The Download feature will be disabled after May 13, 2011) Ouch for being wrong,  and double ouch for having to download all my videos to my hard drive. Notes: Astute readers will note, I actually got a decent deal since I got 8 years of free s...

I'll be honest, I don't know squat about ATM, but I was having lunch with this fellow , and he told me the story of the 53 byte ATM packet.  You can find more details on Wikipedia , but here’s the synopsis: (Disclaimer: I’m not an expert in ATM; nor am I trying to teach you technical details about ATM networks; so I’ll hand wave and trade off accuracy for simplicity. For example, ATM does have variable sized packets which it divides into cells, and it is the cells which are 53 bytes long. However, since the closest thing to a cell in common networks is an Ethernet packet, I’ll simply refer to cells as packets.) ATM is designed to be shared between data network applications, and voice network applications(+). In data networks we want large packets because this gives maximum efficiency.  This is because each packet has a fixed size header and thus the more data you can transmit per packet , the higher your ‘real’ throughput. For voice networks we want to reduce latency...