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---
stand_alone: true
ipr: none
cat: std
status: draft
area: Systems Engineering
wg: OSMORA Standards Group
docname: OAP-0005
title: OSMORA Archive Format
abbrev: OMAR
lang: en
kw:
- omar
author:
- role: editor
name: Ian M. Moffett
org: OSMORA
city: Washington, DC
region: Southeast
code: 20020
email: ian@osmora.org
--- abstract
The OSMORA Archive (OMAR) format is a minimalist replacement for CPIO and TAR perfect
for use in in-memory filesystems and general usage.
--- middle
# Introduction
OMAR is a simple archive format designed to be minimal and useful for general usage
as well as for use in in-memory filesystems.
## Purpose
While CPIO and TAR can also get the job done (in too many different ways, that is),
OMAR simply gets it done while keeping the implementation small and minimal.
# Requirements Language
{::boilerplate bcp14-tagged}
# OMAR header
Before the contents of each file, there MUST be a header that
describes the file contents. This header contains things such as its
magic (for validation), file type, length of the filename and the
length of the file. The file path goes directly after the header
and its length is denoted by the header filename length field. The
actual file contents are directly after the filename, if the total
length of the file is not a multiple of the block size (512) it MUST
be padded to the nearest 512 byte boundary with zeros. All directories
are to be padded with 512 bytes where data would be for regular files.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+--------------------+
| Magic ("OMAR") | - Signature (4 bytes)
|--------------------|
| Type | - File type (1 byte)
|--------------------|
| Namelen | - Length of name (1 byte)
|--------------------|
| Len | - Length of file (4 bytes)
+--------------------+
\/\/\/\/\/\/\/\/\/\/\/
DATA
00 00 00 00 00 00
00 00 00 00 00 00
00 00 00 00 00 00
... padding
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
