genode/os/src/server/part_blk
Martin Stein 9d23cdc27f part_blk: raise max packet size to 1 MiB
This is because the old packet size of 128 KiB slowed
down l4linux AHCI benchmark on arndale with large block sizes.
2013-06-26 15:05:20 +02:00
..
README Imported Genode release 11.11 2011-12-22 16:19:25 +01:00
back_end.cc Update copyright headers to 2013 2013-01-10 21:44:47 +01:00
main.cc Update copyright headers to 2013 2013-01-10 21:44:47 +01:00
part_blk.h part_blk: raise max packet size to 1 MiB 2013-06-26 15:05:20 +02:00
target.mk Merge base libraries into a single library 2013-02-19 14:45:55 +01:00

README

This directory contains an implementation of a block-device-partition server.

Behavior
--------

The server uses Genode's block-session interfaces as both front and back end,
leading to the most common use case where this server will reside "between" a
block-driver server and a higher level component like a file-system server.

At startup, the partition server will try to parse the master boot record (MBR)
of its back-end block session. If no partition table is found, the whole block
device is exported as partition '0'. In the other case, the MBR and possible
extended boot records (EBRs) are parsed and offered as separate block sessions
to the front-end clients. The four primary partitions will receive partition
numbers '1' to '4' whereas the first logical partition will be assigned to '5'.

In order to route a client to the right partition, the server parses its
configuration section looking for 'policy' tags.

XML Syntax:
! <policy labal="<program name>" parition="<partition number>" />

Usage
-----

Configuration snippet with two clients and an (hypothetical) IDE driver:
!<start name="ata_driver">
!  <resource name="RAM" quantum="1M" />
!  <provides><service name="Block"/></provides>
!  <config ata="yes" />
!</start>
!
!<start name="part_blk">
!  <resource name="RAM" quantum="10M" />
!  <provides><service name="Block" /></provides>
!
!  <!-- route part_blk to the ata_driver -->
!  <route>
!    <any-service><child name="ata_driver"/> <parent/><any-child/></any-service>
!  </route>
!
!  <!-- allow program 'test-part1' to access logical partition '6', while program
!      'test-part2' receives access to primary partition 1 -->
!  <config>
!    <policy label="test-part1" partition="6"/>
!    <policy label="test-part2" partition="1"/>
!  </config>
!</start>
!
!<!-- part_blk clients -->
!<start name="test-part1">
!  <binary name="test-part"/>
!  <resource name="RAM" quantum="10M" />
!  <route>
!    <any-service> <child name="part_blk" /> <parent/> <any-child/> </any-service>
!  </route>
!</start>
!
!<start name="test-part2">
!  <binary name="test-part"/>
!  <resource name="RAM" quantum="10M" />
!  <route>
!    <any-service> <child name="part_blk" /> <parent/> <any-child/> </any-service>
!  </route>
!</start>