How fast is 'fast'?
-------------------

There are several machines available now with fast storage. How do they compare?

First on the scene was the i-MX6 from R-Comp launched at the ROUGOL show
in October 2014. This used SCSIfs with an on-board SATA socket. Next was Titanium from Elesar in December 2015 (which saw a speed up from improved software in 2018). This used ADFS with an on-board SATA interface.

The Pinebook Pro was available from R-Comp from August 2020 which has an
option for internal fitting of an NVMe drive for which drivers were made available in 2024.

In February 2023 RISC OS Bits were selling some 'FAST' hardware - a SATA adapter for the Raspberry Pi I/O board with an ADFS driver in ROM. By 2024
this supported drives with 4k sectors.

By 2024 RISC OS Bits and R-Comp had drivers available for M.2 NVMe drives fitted to various proprietary I/O boards and adapters including the DeskPi
Mini (aka PiRO Qube), the Pi Foundation I/O board with a suitable adapter
and the Waveshare Mini I/O board.

Test results
------------

When comparing overall speed there are two principal components: processor speed and storage speed. Since the fastest machines are pretty much all
using the Compute Module 4 (Pinebook Pro using NVMe not yet tested) the
focus has to be on storage speed.

The formatting of a drive can make quite a difference: a small
improvement in speed can be obtained by using a larger LFAU than the
minimum for that partition size, at the expense of disc capacity for small files. This is probably not a good idea on partitons less than 240GB in
size.

A significant improvement in speed can be obtained on an NVMe drive by switching its sector size from 512e to 4k.

A SATA drive formatted to 4k sectors shows a speed improvement for random access but the overall benefit is marginal for 'real world' tasks.

[image https://www.svrsig.org/images/DrTab.jpg width=958 height=406]

[image https://www.svrsig.org/images/pergraph.jpg width=700 height=459]

Conclusion
----------

When formatting a drive, a small improvement in speed can be obtained by
using a larger LFAU than the minimum for that partition size, at the
expense of disc capacity for small files.

The minium LFAU for 512b sectors is 4k for partitions up to 128GB and 8k
for the largest partition size, 256GB. For drives with 4k sectors it is
16k for 512GB, 32k for 1TB and 64k for 2TB, the largest.

Formatting an NVMe drive to 4k sectors improves speed considerably. DOS partitions such as Loader are not supported on 4k discs by DOSFS and
fat32fs but neither are they necessary. Further partitions can be added (provided that an MBR partition table is added to protext the filecore partition) but will only be seen by Linux.

At the London show I shall be demonstrating the 'fastest' machine. I think
that it is a 'dead heat' between a DeskPi Mini IO board using an M.2 1TB
NVMe drive running RISC OS Developments Block Drivers (6-Oct-2024) and a
Pi Foundation IO board using a 1TB 'FAST' SATA drive running RISC OS Bits custom RISC OS rom (28-Jul-2024) with SATA support.

These all use a Compute Module 4 overclocked to 2000MHz or 2147MHz and 1TB drives formatted to 4k sectors.

Formatting a drive to use 4k sectors can be done in RISC OS in the case of
NVMe drives and most drives of 512GB and above seem to support this.

Formatting a SATA drive to 4k sectors requires Linux to do this and I have
not yet managed to do this as a DIY task (the drives I have are 250GB or smaller and the Linux utility reports itself unable to set these to 4k sectors).

Benchmarks [www.svrsig.org/HowFast.htm] have been updated.

--
Chris Hall <chris@svrsig.org>


_______________________________________________________________ a.m.conroy@argonet.co.uk, Moderator of comp.sys.acorn.announce.
Submissions to csaa@owlart.net
Related mail to csaa-request@owlart.net

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)