Cheetah 18FC Installation Guide, Rev. A

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Enabling and disabling the write cache

Write caching is a feature that allows the drive to transfer write data to its own cache, tell the controller that the task is complete, and then actually complete the write at a later time. This improves write performance by freeing the CPU to go on to its next command.

Warning. Information can be lost if you enable write cache and there is a system failure (for example, power failure) before the data has actually been physically written to the disc.

OEM drives are shipped with write cache enabled by default. If you want to disable the write cache, refer to your system’s drive controller and software utility documentation. Seagate provides an ASPI utility that you can use in a PC compatible system to disable the write cache. It is available on Seagate’s CompuServe forum and on the Seagate BBS (refer to “Seagate Technology support services” on page 8).

Connecting remote LEDs

You can connect remote LEDs using J6 (see Figure 4).

Connect the anode (usually the longer LED connector) to the +5V pin, and the cathode to the appropriate LED output pin. For example, if you want to attach an LED which lights up when the drive is active (reading or writing), connect the LED’s anode con- nector to J6 pin 11 and the cathode, through an appropriate external current-limiting resistor, to J6 pin 8 or pin 12.

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Seagate 18FC manual Enabling and disabling the write cache, Connecting remote LEDs