The Coda Logo

The Coda logo was inspired by a cartoon contrasting AFS and Coda. The cartoon was drawn by a Japanese artist, Gaich Muramatsu and appeared in the magazine "Nikkei Electronics". The left half of the cartoon shows unhappy AFS users dealing with a broken network connection to the servers. The figure on the right shows happy Coda users in similar circumstances, thanks to Coda's support for disconnected operation. The distinctive tilt and square shape are characteristic of all Carnegie Mellon logos.


This cartoon is one of many created by Gaich Muramatsu for the September 3 1990 issue of Nikkei Electronics. The cartoons accompanied a translation of the article "Scalable, Secure, and Highly Available Distributed File Access" by M. Satyanarayanan. The original article appeared in IEEE Computer in May 1990. Even if you don't understand a word of Japanese, you can confirm that the translators got the main ideas right by looking at the cartoons. A unique example of an end-to-end check!

Other cartoons

  • Obstacles to distributed data access: the delivery truck with floppies is blocked by the boulder on the path to the user.
  • The concepts of Volume Storage Group (VSG) and Accessible VSG (AVSG): the yellow and green ellipses in the Venn diagram indicate the VSG and AVSG for a volume. The glum-looking guy on the extreme left represents a server not relevant to the volume. The second guy from the left represents a member of the VSG that is partitioned from the client. The two guys on the right represent the current AVSG for the volume; they are in contact with the client via a wireless network connection (the walkie-talkies).
  • The impact of hoarding on cache space: New data (the folks waiting) can't enter the full cache until space is made for them by flushed data (the folks leaving). Hoarded files (the folks in the elevator with "Sticky" on their legs) effectively reduce the amount of space available in the cache.
  • Coda's security model:The servers are trusted (the chain ring and cop), while clients are not (thief at workstation on the right). But even if an intruder violates the security of one client, the data of users working at other clients is safe.
  • Reproduction

    The copyright to these cartoons is held by the artist, Gaich Muramatsu. Use of these cartoons or derivatives for commercial purposes without explicit permission of the artist is a violation of copyright. Carnegie Mellon University has received permission from the artist to reproduce these cartoons for non-commercial purposes.