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Space, the final frontier


Development pace has slowed down. This is inevitable for 100% volunteers driven projects when people don’t have unlimited free time. In the meantime, the interest is growing and some people are looking at their hardware, either to improve Hugin’s performance in Windows or to dual boot Linux-Windows and expand their toolbox, and since Hugin enables the creation of ever larger images, space is the final frontier.

Assuming that CPU, GPU, Motherboard and RAM are held constant, the choice of hard disks layout and controllers can influence both system performance and price tag.

At the time of writing, the sweet spot hard disk size (best price/GB) is 500GB. The only reason to buy other capacities is performance. For a high density storage facility performance is capacity or energy consumption; for a workstation performance is speed.

The two key speed metrics are access time (AT) and sustained transfer rate (STR).

AT is the time it takes to position the head on the right location of the disk. It is measured in ms, with modern 7.2K RPM drives averaging less than 10ms. The noisy and expensive 15K RPM SCSI drives achieve averages of 3ms. The 10K RPM SATA raptors achieve 5ms. Fast AT benefits random, small, frequent, concurrent read/write operations.

STR  is the bandwidth provided once the data transfer has started. Usually one factor is the bottleneck: information density. The new drives with perpendicular recording (500GB, 750GB, 1000GB) have the highest density. A large cache (the new drives have 32MB), as well as defragmented, healthy data, help as well. High STR benefits the transfer of large chunks of data at once.

Whether AT or STR is the relevant bottleneck is determined by the application. Databases and, to a lesser extent, workstation system drives, benefit from AT. Photoshop scratch is an application that benefits from STR rather than AT, and the same is true of many other imaging applications, such as Hugin.

For most imaging uses, 7.2K RPM drives are more than adequate. To further improve system performance, use the latest generation 7.2K RPM drives. To even further improve performance, spread the load across multiple hard disks (not partitions):

  • One disk for the system and application
  • One disk for the data
  • One scratch disk

For further performance increases, use RAID. See the next article for a discussion of RAID.

One Response

  1. Hi,

    I like the article, but I mainly want to thank all those people who made and maintain Hugin.

    Thanks folks, development speed may be slower than you would like, but my appreciation for what you have done couldn’t be higher!

    Ruud

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