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Diffstat (limited to 'hurd/libstore/copy_store.mdwn')
| -rw-r--r-- | hurd/libstore/copy_store.mdwn | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/hurd/libstore/copy_store.mdwn b/hurd/libstore/copy_store.mdwn new file mode 100644 index 00000000..5df5d220 --- /dev/null +++ b/hurd/libstore/copy_store.mdwn @@ -0,0 +1,25 @@ +[[!meta copyright="Copyright © 2000, 2007, 2008, 2009 Free Software Foundation, +Inc."]] + +[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable +id="license" text="Permission is granted to copy, distribute and/or modify this +document under the terms of the GNU Free Documentation License, Version 1.2 or +any later version published by the Free Software Foundation; with no Invariant +Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license +is included in the section entitled [[GNU Free Documentation +License|/fdl]]."]]"""]] + +[[!meta title="copy store: copy-on-write; discard changes on termination"]] + +A *copy* store is meaningful only with respect to a child store. What a *copy* +store does is to read the child store's entire contents into memory at startup +time and then use that buffer as the contents of the store thereafter. (The +code for this is in `libstore/copy.c`.) + +Because of how the interfaces are specified, reading the entire contents of a +[[*zero* store|zero store]] in fact means just `vm_allocate`ing fresh memory. +So, a *copy* store based on a [[*zero* store|zero store]] is just what you'd +get from `vm_allocate`ing some memory and passing it into +`store_buffer_create`. + +See a [[ramdisk example|examples/ramdisk]]. |