exercise_disk lacks test size control and "progress bar"

[canthony]

exercise_disk's random test takes six and a half hours to run; it has no progress indication, nor a method for doing a shorter test.

Add a "-loops" parameter to limit the size of the test.

Add a "progress bar" during the test so as to allow an estimated time to completion.

[pwd]>exercise_disk d501 cac -loops 10000

exercise_disk: Device type is d501 pack serial no. is cac
exercise_disk: exercise_disk will destroy all data on this pack !

exercise_disk: Do You Wish To Continue?   yes
exercise_disk: Requesting mount of volume cac.

exercise_disk: Begin random test on dskb_01 (d501) @  1121.1
0%.........10%.........20%.........30%.........40%.........50%.........60%.....
\c....70%.........80%.........90%.........100%

exercise_disk: Testing Completed for dskb_01 (d501).
Test Summary:
Number of Sectors Written           5000
Number of Sectors Read              5000

(Strictly speaking, "-loops" is a misnomer here; it actually sets the number of reads and writes, of which there are four for every loop.)

[canthony]

exercise_disk.pl1