About ReadSpeed

  • Release Candidate 6
    We are at a “proposed final” true release candidate with nothing known remaining to be changed or fixed. For the full story, please see this page in the "Pre-Release Announcements & Feedback" forum.
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GRC's hyper-accurate, mass storage
read-performance benchmark
For those who don't already know, this “ReadSpeed” benchmark utility was created as a test platform for the new “bare metal” hardware mass storage drivers that Steve has developed for SpinRite. Feedback about the successful – and especially any unsuccessful – operation of this benchmark will help to finalize this new technology and will directly feed into SpinRite's release.

“ReadSpeed” locates IDE, SATA and eSATA drives – spinning or solid state – connected to IDE-emulating (legacy) or AHCI (modern) PCI motherboard and add-on controllers. It benchmarks each drives' continuous large-block read performance at five locations across the drive.

With extreme precision it accurately measures the time required to read one gigabyte (2^30 or 1,073,741,824 bytes) consisting of two million (2^21 or 2,097,152) contiguous 512-byte sectors. Recognizing that modern spinning drives store much more data around their larger outer cylinder than around their smaller inner cylinder, ReadSpeed measures the performance at the drive's 0%, 25%, 50%, 75%, and 100% locations.

Spinning drives exhibit as much as a 50% reduction in performance at the end (inner cylinders) of the drive compared with their front (outer cylinders). And during the development of this benchmark, many of us were quite surprised to discover that our solid-state drives (SSDs) were not performing uniformly across their storage space. Many of us found that the front of the SSD – typically where the system's operating system is located – is performing much more slowly than the SSD's other regions. Since identical newer drives exhibit uniform performance, this appears to be the result of long-term use and the storage management associated with wear leveling. We will be investigating this much further.

Getting up to ReadSpeed

“ReadSpeed” is an old school (very old school) MS-DOS compatible application. To be run, DOS must first be booted on a computer system, then the command rs (with optional arguments) is issued to start and run the benchmark. Its output will be displayed to the screen and logged to a file.

The easiest way for Windows users to run ReadSpeed is to run GRC's “ReadSpeed” Windows program. It will reformat any USB-connected thumb drive, make it DOS bootable by installing a copy of the FreeDOS operating system and some miscellaneous DOS programs including RS.EXE -- ReadSpeed for DOS.

You should obtain “ReadSpeed” for Windows from GRC's ReadSpeed web page.

On that page, Linux users without access to Windows can download a bootable drive image which can be written to USB with Linux's 'dd' command, and anyone who already has the ability to boot and run DOS can download the “RS.EXE” DOS program from that page at GRC.

Our ReadSpeed forums

Please check out our other ReadSpeed forums (see the links in the block at the upper left). Those forums will provide community help and insight into booting to DOS, running ReadSpeed, interpreting its results, and reporting any problems you may encounter.

If ReadSpeed has problems

ReadSpeed's “bare metal” hardware driver technology has been developed for the forthcoming release of SpinRite v6.1. If you are a SpinRite owner, you can help to assure that SpinRite will run at its new screaming speed on all your systems by assuring that ReadSpeed runs properly. Since it is our intention that SpinRite will be able to run on all systems and drives, we want to know if ReadSpeed fails to find or run on any of your systems' mass storage drives.

The threads, dialogs and community are here to receive and help you to diagnose and respond to reports of any problems with ReadSpeed.

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