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FAQ_01_Frequently asked questions

mhtvsSFrpHdE edited this page Jan 30, 2023 · 16 revisions

Frequently asked questions

This software is bugged...

Sign up GitHub and create new issue here: https://github.com/mhtvsSFrpHdE/prefetch/issues The fact is, if you never create issue and just complaint on twitter or youtube,
I may never know there is a bug. I only use limited features in daily.

I also not possible to fix every bug, but at least to let me know,
then there is a chance. If I don't know at all, the chance will be completely zero.

Compare to other solutions

https://github.com/mhtvsSFrpHdE/prefetch/wiki/FAQ_Compare-to-other-solutions

Crash when prefetch >= 2 GB files (32 bit out of memory)

Checkout ReadBufferSize.

This is file based, how to selective cache virtual machine disk file or database?

For virtual machine, deploy prefetch instance inside each of it.
For database, good luck with some SSHD solutions.

Any good tips for using SSHD?

Turn off Windows prefetch can bring better SSHD cache hit:
Windows prefetch is a black box and very not configurable.

With prefetch turn on, until disk idle, 7 GB were read from HDD.
With prefetch turn off, only 2.8 GB were read.
Less total read often let SSHD algorithm runs better for what data are really commonly used.

By my experience, Windows prefetch just fill RAM cache with some trash that I never used.
For example, my Firefox program never being cached by prefetch:
Even this is the most commonly open-close-open-close program on my computer.
Each time I feel I need Firefox, Windows always read it from HDD and slow.

You may improve cache hit rate from 60% to 89% by turn it off
on a 60 GB used space partition with 12 GB SSD cache.
To do this, simply disable "SysMain" Windows service.
I don't see any side effect on my gaming PC even two months has passed.

HDD ultimate performance guide

https://github.com/mhtvsSFrpHdE/prefetch/wiki/FAQ_HDD-ultimate-performance-guide

Contribute

https://github.com/mhtvsSFrpHdE/prefetch/wiki/FAQ_Contribute

Can I use source code for...

Start from 1.3 (not include 1.3), source code publish under "JDBM License" together with AGPL.
See https://github.com/mhtvsSFrpHdE/jdbm-license/blob/main/LICENSE_JDBM
You can either choose AGPL version or convert JDBM to compatible with what you are using.

Start from 4.0.4 (not include 4.0.4), source code publish under "JDBM License" together with MIT.
This reduces the infectivity of open source license viruses.

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