1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
|
.. RST source for alf(1) man page. Convert with:
.. rst2man.py alf.rst > alf.1
.. include:: ver.rst
.. |date| date::
===
alf
===
-------------------------------
create Atari 8-bit ALF archives
-------------------------------
:Manual section: 1
:Manual group: Urchlay's Atari 8-bit Tools
:Date: |date|
:Version: |version|
SYNOPSIS
========
alf [**--help**] | [**-a** | **-o** ] *alf-file* *file* [*file* ...]
DESCRIPTION
===========
**alf** creates *ALF* archives.
*ALF* is a compressed archive format similar to **arc**\(1), though
not compatible with it. It was used on the Atari 8-bit platform
beginning in the late 1980s. The Atari executables are **LZ.COM**
for the compressor and **DZ.COM** for the decompressor. **alf** is a
rewrite of **LZ.COM** for modern operating systems, with added features.
By default, the *alf-file* is created, and the *file*\s are compressed
and added to it. If *alf-file* already existed, it is backed up by adding
a **~** to the filename.
The **ALF** file format only supports uppercase "8.3" filenames
(Atari DOS or MS-DOS style), and does not support subdirectories. The
filenames you give will be stored in the **ALF** file uppercased
and truncated to fit the 8.3 scheme. This could result in duplicate
filenames in the archive, if you're not careful.
OPTIONS
=======
-a
Append to *alf-file*. The files are added to the end of the archive. Be
careful not to add a file with the same name as as existing member of
the archive. If *alf-file* doesn't exist, it will be created. No backup
is made with **-a**.
-o
Overwrite *alf-file* if it exists; do not make a **~** backup.
EXIT STATUS
===========
0
Success.
1
Fatal error (I/O or bad command-line arguments).
NOTES
=====
Compatibility
-------------
This **alf** is *intended* to be 100% compatible with the original
Atari **LZ.COM** aka **ALF.COM**, with the following differences:
- There is no interactive mode. The file to create and the files to add
must be given as command-line arguments.
- **LZ.COM** always appends to a file that already exists. This **alf**
overwrites (making a backup) by default, and can append with the **-a**
option.
- Turning the screen off for speed makes no sense on modern operating
systems, so there's no option for that.
Note that **alf** is a complete reverse-engineered rewrite in C, *not*
a port of the original 6502 code as **unalf** is. It's still being
tested, and may still contain bugs.
File Size Limits
----------------
**alf** (and **LZ.COM**) have a 16MB file size limit. **uanlf**
actually can't handle files above about 15MB, if you compress one with
**alf**. Real Atari 8-bit files are never this large anyway, so it's
a pathological case. A real Atari would take hours or even days to
compress/decompress such files, and you'd have to have a hard disk and
a DOS capable of handling multi-megabyte files...
It's also impossible to compress empty (0-byte) files. **alf** will
skip them, if any are found.
Performance
-----------
Performance is *horrible*. This shouldn't be a real problem on
modern multi-GHz CPU, especially since most Atari 8-bit files are
small (usually under 64KB). Interestingly, it's not O(n^2), it scales
linearly, O(1): Compressing a 1.3MB text file takes 0.7 seconds on the
author's (rather modest) Intel i7 workstation, and a file 10x as large
takes approximately 10x as long (7 seconds). A 50KB file is almost
instantaneous, 0.05 seconds, which is more typical of the files you'd
actually use this with.
Timestamps
----------
The date/time stamps stored in the archive are the **mtime**\s of
the files (which is the same time **ls**\(1) shows, by default), and
your local timezone is assumed. Only a 2-digit year is displayed by
**unalf**, but the year stored in the *ALF* file doesn't have a Y2K
problem. It does, however, have a Y2108 problem...
COPYRIGHT
=========
The original AlfCrunch (**DZ.COM** and **LZ.COM**) for the Atari 8-bit
was released into the Public Domain. **alf** contains no code from
AlfCrunch.
**alf** is released under the WTPFL: Do WTF you want with this.
AUTHOR
======
The original AlfCrunch for the Atari 8-bit was written by Alfred, who
can be reached via the AtariAge.com forums with the username "Alfred".
This **alf** was written by B. Watson <urchlay@slackware.uk>.
SEE ALSO
========
**unalf**\(1), **alfls**\(1)
.. include:: manftr.rst
|
