Q8.6: Why place tempdb and log on low numbered devices?

System 10 and below.
In System 10 and Sybase 4.X, the I/O scheduler starts at logical device (ldev) zero and works up the ldev list looking for outstanding I/O's to process. Taking this into consideration, the following device fragments (disk init) should be added before any others:
  1. tempdb
  2. log