Western Digital AC25100 5.1GB 3.5" IDE Hard Drive WD Caviar 40-Pin ATA

Western Digital AC25100 5.1GB 3.5" IDE Hard Drive WD Caviar 40-Pin ATA

The Western Digital AC25100 is a 5.1GB 3.5-inch IDE hard drive from Western Digital's WD Caviar series. It uses a standard 40-pin ATA interface and connects via a 4-pin Molex power connector, making it a direct drop-in for any desktop PC of the era with a standard IDE controller. The drive was manufactured in August 1998 in Singapore.

Specifications & What's Included

• Brand: Western Digital
• Model: AC25100 (WD Caviar 25100)
• Part Number: AC25100-00LKK2
• Capacity: 5.1 GB (5163.5 MB formatted)
• Form Factor: 3.5" internal
• Interface: 40-pin IDE (ATA/PATA)
• Drive Parameters: 10,672 cylinders / 15 heads / 63 sectors per track
• Power: 5VDC @ 0.64A, 12VDC @ 0.24A
• Date of Manufacture: 26 August 1998
• Made in: Singapore
• Certifications: UL, CSA, CE, BZUI
• Jumper settings diagram printed on drive label (Master/Slave/Cable Select)
• Drive only — no cables or mounting hardware included

Applications

The WD Caviar AC25100 is a late-1990s IDE hard drive designed for desktop PCs using the ATA (PATA) interface standard. Drives in this capacity range were mainstream desktop storage in the 1996–1999 period, commonly used as primary or secondary drives in Windows 95, Windows 98, and early Windows NT systems, as well as Linux and DOS machines of the same era. Today these drives are primarily sought for retro PC builds, vintage computer restorations, and legacy industrial or embedded systems that require an IDE drive and cannot accept modern SATA hardware. The 40-pin ATA interface was nearly universal in desktop and tower PCs through the early 2000s before SATA displaced it, so compatibility with period-correct hardware is broad. The WD Caviar line was one of Western Digital's flagship desktop drive families through the 1990s and is well-regarded for reliability in retro computing circles.