Sony VGC-RA810G - Manual (Page 197)

About Hard Disk Drive Installation
Your computer comes with an available internal bay to hold another 3½-inch hard disk drive. Some models, such as
Configure-to-Order (CTO) systems, may already have additional hard disk drives installed.
When you install an additional hard disk drive, such as an SATA drive, the method of attaching connectors and cables may
vary from the instructions in this section. Review the information provided with your new hard disk drive before attempting
to install it in your computer.
The hard disk drive access light blinks when either internal hard disk drive is active.
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