.\"	$OpenBSD: presto.4,v 1.5 2010/07/11 07:37:30 jmc Exp $
.\" Copyright (c) 2003, Miodrag Vallat
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.Dd $Mdocdate: July 11 2010 $
.Dt PRESTO 4 sparc
.Os
.Sh NAME
.Nm presto
.Nd Prestoserve battery-backed memory
.Sh SYNOPSIS
.Cd "presto* at sbus?"
.Sh DESCRIPTION
The
.Tn Legato
Prestoserve NVRAM cards
used to be part of the
.Dq NFS accelerator
product, which used the cards memory as an NFS-dedicated cache, increasing
performance of NFS servers exporting filesystem as NFS protocol, version 2.
.Pp
The
.Nm
driver does not attempt to achieve such a behaviour, which is questionable
with the advent of NFS protocol, version 3.
.Pp
Instead, it will provide direct access to the NVRAM, as a block device.
.Sh FILES
.Bl -tag -width /dev/rprestoXXXXX -compact
.It Pa /dev/presto Ns Ar u Ns Ar p
block mode Prestoserve card number
.Ar u ,
partition
.Ar p
.It Pa /dev/rpresto Ns Ar u Ns Ar p
raw mode Prestoserve card number
.Ar u ,
partition
.Ar p
.El
.Sh SEE ALSO
.Xr intro 4 ,
.Xr disklabel 5 ,
.Xr disklabel 8 ,
.Xr MAKEDEV 8
.Sh BUGS
The NVSIMM flavour, designed for SPARCstation models 10 and 20, is not
supported yet.