diff options
| author | B. Watson <urchlay@slackware.uk> | 2025-11-26 17:53:35 -0500 |
|---|---|---|
| committer | B. Watson <urchlay@slackware.uk> | 2025-11-26 17:53:35 -0500 |
| commit | e9d1cc997a2e6f8a54974c832182aaa9a5f15939 (patch) | |
| tree | 49570c6b5262d86c973b0343a59d3d9faebb241b /src/alf.1 | |
| parent | db64ce4dbbd6c1cf273ce1e557158301ff4a9228 (diff) | |
| download | unalf-e9d1cc997a2e6f8a54974c832182aaa9a5f15939.tar.gz | |
Update notes in alf man page.
Diffstat (limited to 'src/alf.1')
| -rw-r--r-- | src/alf.1 | 12 |
1 files changed, 11 insertions, 1 deletions
@@ -77,6 +77,7 @@ Success. Fatal error (I/O or bad command\-line arguments). .UNINDENT .SH NOTES +.SS Compatibility .sp This \fBalf\fP is \fIintended\fP to be 100% compatible with the original Atari \fBLZ.COM\fP aka \fBALF.COM\fP, with the following differences: @@ -88,11 +89,15 @@ must be given as command\-line arguments. \fBLZ.COM\fP always appends to a file that already exists. This \fBalf\fP overwrites (making a backup) by default, and can append with the \fB\-a\fP option. +.IP \(bu 2 +Turning the screen off for speed makes no sense on modern operating +systems, so there\(aqs no option for that. .UNINDENT .sp Note that \fBalf\fP is a complete reverse\-engineered rewrite in C, \fInot\fP a port of the original 6502 code as \fBunalf\fP is. It\(aqs still being tested, and may still contain bugs. +.SS File Size Limits .sp \fBalf\fP (and \fBLZ.COM\fP) have a 16MB file size limit. \fBuanlf\fP actually can\(aqt handle files above about 15MB, if you compress one with @@ -101,14 +106,19 @@ a pathological case. A real Atari would take hours or even days to compress/decompress such files, and you\(aqd have to have a hard disk and a DOS capable of handling multi\-megabyte files... .sp +It\(aqs also impossible to compress empty (0\-byte) files. \fBalf\fP will +skip them, if any are found. +.SS Performance +.sp Performance is \fIhorrible\fP\&. This shouldn\(aqt be a real problem on modern multi\-GHz CPU, especially since most Atari 8\-bit files are small (usually under 64KB). Interestingly, it\(aqs not O(n^2), it scales linearly, O(1): Compressing a 1.3MB text file takes 0.7 seconds on the author\(aqs (rather modest) Intel i7 workstation, and a file 10x as large takes approximately 10x as long (7 seconds). A 50KB file is almost -instantaneous, 0.5 seconds, which is more typical of the files you\(aqd +instantaneous, 0.05 seconds, which is more typical of the files you\(aqd actually use this with. +.SS Timestamps .sp The date/time stamps stored in the archive are the \fBmtime\fPs of the files (which is the same time \fBls\fP(1) shows, by default), and |