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
|
<!--
libexplain - Explain errno values returned by libc functions
Copyright (C) 2009, 2010 Peter Miller
Written by Peter Miller <pmiller@opensource.org.au>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or (at
your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
-->
.hy 0
.ad l
<!DOCTYPE HTML PUBLIC
"-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/1999/REC-html401-19991224/loose.dtd"
>
.nf
<html>
<head>
<title>
No Medium Found, 1.0, Notes
</title>
</head>
<body>
<table width="100%" >
<tr>
<td align="left" >
<a href="000-notes.html" >Prev</a>,
<a href="000-notes.html" >Top</a>
</td><td align="right" >
<a href="100-slide.html" >Slide</a>,
<a href="200-notes.html" >Next</a>
</td>
</tr>
</table>
<h1>
1. Motivation
</h1>
<img src="dowser.png" align="right" alt="" />
<ul>
<li>
1983
<li>
over 500 system calls × multiple errors = 8 bits of <i>errno</i> ?!?
; <a href="100-slide.html" >slide</a>
<li>
disconnect:
<ul>
<li> the user has no idea
<li> the kernel knows
</ul>
<li>
The car is up on the hoist, and we are locking at the underside.<br/>
Mud, crud, and ugly (functional, but ugly).
</ul>
<h2> 1.1 Error Messages as Finesse </h2>
<ul>
<li> each is < 1% of project effort
<li> user benefit exceeds effort
<li> what the errors look like to the user
<ul>
<li> segfault; <a href="110-slide.html" >slide</a>
<li> can't open file; <a href="130-slide.html" >slide</a>
<li> perror("open"); <a href="140-slide.html" >slide</a>
<li> perror(filename); <a href="150-slide.html" >slide</a>
<li> "open %s: %s", filename, strerror; <a href="160-slide.html" >slide</a>
</ul>
</ul>
<h2> 1.2 Limitations of perror and strerror </h2>
<ul>
<li> describes the error <i>number</i>; <a href="170-slide.html">slide</a>
<li> the kernel knows; <a href="171-slide.html" >slide</a>
<li> the file name problem; <a href="172-slide.html">slide</a>
<li> 1980s, PDP11, no resources
</ul>
<h2> 1.3 Level Infinity Support </h2>
<ul>
<li> Never <i>ever</i> talk to users; <a href="180-slide.html">slide</a>
<li> Test team need translations; <a href="181-slide.html">slide</a>
<li> Level 1 help desk need translations
<li> Enough! ; <a href="182-slide.html">slide</a>
</ul>
</body>
</html>
|
