What is a HDD?
Hard drive disk (HDD) are data storing devices. They store data on spinning disks, magnetically. HDD have several read and write heads over these spinning disks, which as the names suggest read from and write data on the disks.
On energy-efficient hard drives, thee disks spin at a rate of 4,200RPM, while on high performing serves, this number can reach up to 15,000 RPM. HDD’s found in most laptops spin at a rate of 7200-7500 RPM, which offers a transfer rate of 100-200MBps.
Advantages
- Cheaper than SSD in terms of dollar to gigabyte
- Longer lifespan, ideal for server computers
Disadvantages
- Emits more heat
- Inefficient than SSD
- Consume more power
- Larger in size and weigh more than SSD, not ideal for laptops
- Less shock resistant
- Slower than SSD
- Latency issues (The time taken by the specific block of data on a data track to rotate around to under the read-write head)
HDD Storage Capacities
HDD’s capacity can range anywhere from 120GB to 20TB, while Toshiba offers HDD in 4GB and 8GB storage capacity as well.
HDD Data Transfer Rate
| External drive | Transfer Rate |
| USB 1.1 | Up to 12 Mbits/sec |
| USB 2.0 | Up to 480 Mbits/sec |
| USB 3.0 | Up to 4.8 Gbits/sec |
| 1394a (Firewire 400) | Up to 400 Mbits/sec |
| 1394b (Firewire 800) | Up to 800 Mbits/sec |
| eSATA | Up to 1.5 or 3.0 Gbits/sec |
| Thunderbolt | Up to 10 Gbits/sec |
| Internal drive | Transfer Rate |
| UltraATA 100 | Up to 100 Mbytes/sec |
| Serial ATA 1.5 | Up to 1.5 Gbits/sec |
| SATA 3.0 | Up to 3.0 Gbits/sec |
| SATA 6.0 | Up to 6.0 Gbits/sec |
| Serial-Attached SCSI (SAS) | Up to 1.5, 3.0, 6.0, or 12.0 Gbits/sec |
The data used in the tables was taken from Seagate.
Manufacturers
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For laptops with HDDs you can check the following articles
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