Operating System Design and Implementation, 15-412

README for project 1:

  Everything works all right (or at least it seems so).
  The clock runs at about half the speed on the linux clusters (wean), but
  runs more or less accuratly when doing remote login.

  I'm using a ring buffer of size 128 bytes to save the keys in the keyboard
  handler. I don't have any concurrency problem at this level, but I'm still
  disabling the interrupts as requested. Anything that comes in when the buffer
  is full is ignored. Reading from the empty buffer returns -1.
  
  The format for setting the clock is exactly the same as sscanf("%d %d %d\n")
  (one or two digits for hour, any number of spaces, one or two digits for
  minutes, any number of spaces, one or two digits for seconds, new line)

  I'm using two variables to keep track of the time. One variable is the timer
  value that starts at 0 and keeps on incrementing. The other one is
  the previous time displayed, which is updated by calculating how much time
  has elapsed since last update.

  The \r is added to the \n in the kernel when the keys are extracted by
  readchar(). It seems some people are doing this in the console.

  The console.h has two extra functions: isHidden and getLine. Get line
  just returns a pointer to the beginning of the line in console memory where
  the cursor is. isHidden is used to check the cursor state and restore it
  exactly (in display time).

Alok Menghrajani
amenghra@andrew.cmu.edu