Re: A plan for parameterized packages

[Denis 'GNUtoo' Carikli <GNUtoo@cyberdimension.org>]

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On Sun, 15 Nov 2020 22:24:29 +0100
raingloom <raingloom@riseup.net> wrote:
> Alpine already achieves an incredibly tiny install size by splitting
> packages into many outputs. We could and should do the same.
> As far as I know, they do not have parameterized packages.
That also depends on how far you want to go.

Last time I looked into how LibreCMC/OpenWRT did that, they had much
more optimization than that. If I recall well, they use at least:
- sstrip to strip binaries as much as they could. sstrip produces
  smaller binaries than with strip.
- compilation flags like -Os
- a read-only compressed filesystem with an overlay to store the
  changes

The issue is that despite all that, the size of the images tend to
increase too rapidly over time[1].

If we manage to shrink Guix enough, it might be possible to use it on
way more devices, including RYF compliant devices or potentially
certifiable devices:
- The Talos II BMC has 32M according to both the wiki[2] and the image
  sizes[4]. Its architecture is ARM. So once we have the PPC64
  architecture working, it would be great to be able to run Guix
  both in the BMC and on the PowerPC CPU.

  That BMC is also available on other mainboards like the D16 which is
  supported by Libreboot, but the flash size is probably even smaller
  there.
- Many WiFi access point have very few flash space. It can boils down
  to as low as 16M for LibreCMC/OpenWRT compatible devices, or even 8M
  for older devices. However they typically use the MIPS architecture
  which isn't supported yet in Guix.
- There is a GNU/Linux distribution[6] that runs inside the flash chip
  where Libreboot or Coreboot typically runs. The goal is to enable
  more flexible and/or secure booting by using GNU/Linux to boot
  GNU/Linux. Here too the flash chip of computers supported by
  Libreboot can be quite small, like 8M for Thinkpads with GM45
  chipsets.

In some case it might be possible to increase the flash chip size
(sometimes you don't need soldering for that), but at least with x86
mainboards, the chipset has limits on the size of the flash chip that it
can see. And the size cannot be increased that much: The biggest flash
chip that flashrom supports is 256M.

References:
-----------
[1]https://openwrt.org/supported_devices/864_warning
[2]The wiki[3] mention a MX25L25635F/MX25L25645E/MX25L25665E flash chip
   which is 32M according to flashrom -L
[3]https://wiki.raptorcs.com/wiki/Debricking_the_BMC#Flash_new_BMC_firmware_via_serial_port_.28Open_Source_Method.29
[4]Once uncompressed the image[5] size (for installation through the
   shell) is 32M.
[5]https://wiki.raptorcs.com/wiki/File:Talos-ii-openbmc-v2.00-bundle.tar
[6]https://github.com/osresearch/heads/
[7]https://github.com/osresearch/heads/tree/master/config

Denis.

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