ref: 728eff896074bfa69130c243941ffc6d5c19a735
dir: /man/2/venti/
.TH VENTI 2 .SH NAME Venti \- access to Venti content-addressed filestore. .SH SYNOPSIS .EX include "venti.m"; venti := load Venti Venti->PATH; Session: import venti; init: fn(); Session: adt { new: fn(fd: ref Sys->FD): ref Session; read: fn(s: self ref Session, score: Venti->Score, etype: int, maxn: int): array of byte; write: fn(s: self ref Session, etype: int, buf: array of byte): (int, Venti->Score); sync: fn(s: self ref Session): int; }; Score: adt { a: array of byte; eq: fn(a: self Score, b: Score): int; text: fn(a: self Score): string; parse: fn(s: string): (int, Score); zero: fn(): Score; }; .EE .SH DESCRIPTION .I Venti is a block storage server intended for archival applications. The .I Venti module provides low-level access to a Venti server. The module assumes that the physical connection to the server has already been established (for example, by .IR dial (2)). On a Venti server, a block is addressed by the SHA1 hash of the contents of that block, known as a .IR score , and represented as a .B Score adt. Blocks are additionally tagged with a .IR type , facilitating recovery in the event of corruption. A .B Session represents a session with a Venti server. .TP .IB s .new(\fIfd\fP) .B New performs the initial handshake with the Venti server, returning established .BR Session . .TP .IB s .read(\fIscore\fP,\ \fIetype\fP,\ \fImaxn\fP) .B Read tries to retrieve the block corresponding to .IR score , and of type .IR etype . The block must be no longer than .I maxn bytes. .I Etype is conventionally one of the constants .BR Roottype , .BR Dirtype , .BR Datatype or .BR Pointertype [0-9], where the different .BR Pointertype s represent different depth levels within a Venti tree. .TP .IB s .write(\fIetype\fP,\ \fIbuf\fP) .B Write writes the data in .I buf to the Venti server. The block will be tagged with type .IR etype . It returns a tuple, say .RI ( ok ,\ score ); on error, .I ok is -1, otherwise .I ok is 0 and .I score contains the Venti score for the block that has been written. .TP .IB s .sync() .B Sync tells the Venti server to make sure that all data is committed to active storage. .SH SOURCE .B /module/venti.m .br .B /appl/lib/venti.b .SH BUGS