Sony PCV-RZ30C - Manual (Page 173)

About Hard Disk Drive Installation
Your computer comes with an available internal bay to hold a second standard 3½-inch hard disk drive. Some models, such
as Configure-to-Order (CTO) systems, may already have a second hard disk drive installed. Your system can support
ATA-33, ATA-66, or ATA-100 hard disk drives. Sony recommends using an ATA-100 hard disk drive to take full advantage of
your system's features.
The hard disk drive access light blinks when either internal hard disk drive is active.
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