Compaq AP550 Compaq Professional Workstation AP550 Maintenance & Service G - Page 168

7-12 Compaq Professional Workstation AP550 Maintenance and Service Guide Table 7-10 250-MB Zip Drive Disk Data transfer rate Maximum Sustained 250-MB Cartridge 2.4 MB/sec 100-MB Cartridge Read 1.4 MB/sec Write 0.25 MB/sec Burst (both cartridges) 11.11 MB/sec Seek time (includes settling time)* Minimum 4 ms Average 29 ms Maximum 56 ms Latency (average rotational delay) Spindle speed 2941 rpm Track-to-track access time** Average head switch time# 5 ms 11 ms Head reload time † 700 ms Start-stop time (average) ‡ Start 5 seconds Stop 2 seconds * Seek time does not include latency or head switch time. Average seek time is the average time of a random seek. ** Time from end of last sector on a track to start of next sequential sector on the next track. # Time to switch track following on one data surface and establish track following on other data surface. The average head/switch time is measured over 1,000 accesses (head switches occur for only one-half of random accesses). † Time required for the head to establish track following from the parked position. ‡ Start time is time from disk insertion to time drive is ready to process commands. The typical spin up time for a cartridge that has spun down without ejecting is three seconds. If the drive has difficulty spinning up the motor or reading the z-tracks, it will automatically retry the operation. Software that is waiting for the drive to spin up should set timeouts to no less than 15 seconds to allow time for all retries. Stop time is the elapsed time between pushing the cartridge eject button and the time the solenoid releases the disk.