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Silver 3.5 inch bare hard drive with exposed circuit board

Seagate

Seagate ST3402111A 40GB 7200 RPM 2MB Cache IDE 3.5" internal hard drive

SKU CH-9CHX-F2R20 MPN ST3402111A

A 40 GB 7200 RPM IDE desktop hard drive with 2 MB cache and 11 ms seek time for legacy system upgrades

  • Total capacity40 GB
  • Interface typeIDE Ultra ATA100 / ATA-6
  • Form factor3.5 in (8.89 cm)
  • Packaging typeBare Drive
  • Rotational speed7,200 RPM
  • Cache memory2 MB
  • 7200 RPM spindle delivers responsive desktop performance
  • 40 GB capacity stores essential files and applications
  • 2 MB cache buffers frequent read operations
  • 11 ms average seek reduces data access delay
  • IDE Ultra ATA100 interface connects to legacy motherboards

Legacy desktop upgrade

The Seagate BarraCuda 7200.9 ST3402111A is a 40 GB 3.5-inch internal hard drive built for older desktop PCs that still rely on the IDE Ultra ATA100 / ATA-6 interface. It spins at 7200 RPM with a 2 MB cache and delivers an 11 ms average seek time. The bare drive arrives new and RoHS compliant for straightforward installation in compatible bays.

Builders maintaining vintage systems

This drive suits hobbyists restoring period-correct Windows XP or early Linux machines, or anyone replacing a failed IDE disk in legacy industrial equipment. Buyers whose motherboards lack a native 40-pin IDE connector should look elsewhere, as no adapter is included and the interface cannot be converted by the drive itself.

IDE Ultra ATA100 / ATA-6 interface

The single specification that determines fit is the IDE Ultra ATA100 / ATA-6 connection; the drive will only work in systems that provide this exact 40-pin parallel interface and a standard 3.5-inch mounting bay. Confirm the host has an available IDE channel before purchase.

How it compares

Measured against everything we stock in 3.5-Inch Internal Desktop HDDs, at today’s prices. Recalculated every night.

Price $32.99
Cheaper than about 91% of the 4,938 comparable items (median $107.99).
Total capacity 40 GB
Lower than about 99% of the 2,372 comparable items (median 2 TB).
Price per TB $824.75 per TB
Pricier than about 90% of the 2,365 comparable items (median $62.21 per TB).

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Specifications

Product
Brand nameSeagate
Product lineBarraCuda 7200.9
Model nameST3402111A
Total capacity40 GB
Performance
Rotational speed7,200 RPM
Average seek time11 ms
Mean write time12 ms
Mean latency4.16 ms
Storage
Cache memory2 MB
Ports & slots
Interface typeIDE Ultra ATA100 / ATA-6
Size & build
Form factor3.5 in (8.89 cm)
Shipping weight0.58 kg
Package size203 × 152 × 51 mm

Questions about this item

What does the 7200 RPM spindle speed mean for everyday use?

The drive spins at 7200 RPM with an 11 ms average seek time and 4.16 ms latency, giving responsive access for operating system and application loads.

How does the IDE Ultra ATA100 / ATA-6 interface limit performance?

The ATA-6 interface caps burst transfer at 100 MB/s, so sustained throughput will stay below that ceiling in any system.

Will this 3.5 inch drive fit a standard desktop bay?

The 3.5 inch form factor with 1.0 inch height matches a standard low-profile desktop drive bay and uses a 40-pin IDE connector.

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