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
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
<html>
<head>
<META NAME="generator" CONTENT="lgazmail v1.1G.e">
<TITLE>The Answer Guy 36:
Using only 64Mb out of 128Mb Available
</TITLE>
</HEAD><BODY BGCOLOR="#FFFFFF" TEXT="#000000"
LINK="#3366FF" VLINK="#A000A0">
<!-- ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: -->
<H4>"The Linux Gazette...<I>making Linux just a little more fun!</I>"</H4>
<P> <hr> <P>
<!-- ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: -->
<center>
<H1><A NAME="answer">
<img src="../../gx/dennis/qbubble.gif" alt="(?)" border="0" align="middle">
<font color="#B03060">The Answer Guy</font>
<img src="../../gx/dennis/bbubble.gif" alt="(!)" border="0" align="middle">
</A></H1>
<BR>
<H4>By James T. Dennis,
<a href="mailto:answerguy@ssc.com">answerguy@ssc.com</a><BR>
Starshine Technical Services,
<A HREF="http://www.starshine.org/">http://www.starshine.org/</A>
</H4>
</center>
<p><hr><p>
<!-- ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: -->
<!-- begin 63 -->
<H3 align="left"><img src="../../gx/dennis/qbubble.gif" height="50" width="60"
alt="(?) " border="0">
Using only 64Mb out of 128Mb Available
</H3>
<p><strong>From Terry Singleton on Thu, 17 Dec 1998
</strong></p>
<!-- ::
Using only 64Mb out of 128Mb Available
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
:: -->
<P><STRONG><IMG SRC="../../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
When I run the admin tool "<tt>top</tt>" it appears as if my system
is only using 64MB of memory.
</STRONG></P>
<pre><strong> 11:00am up 4 days, 23:39, 2 users, load average: 0.07, 0.03, 0.00
40 processes: 39 sleeping, 1 running, 0 zombie, 0 stopped
CPU states: 0.3% user, 0.1% system, 0.0% nice, 99.6% idle
Mem: 64168K av, 57420K used, 6748K free, 19820K shrd, 19816K buff
Swap: 104384K av, 24K used, 104360K free 23932K cached
</strong></pre><P><STRONG>
The results show 64168K av which indicates 64168K of available memory yet
our system has 128MB RAM? I have the same results on 2 other Linux servers
with more than 64MB RAM.
</STRONG></P>
<P><STRONG>
I am running RedHat 5.1, is there anything <EM>special</EM> I have to do to tell
the system I have more than 64MB, recompile the kernel..?
</STRONG></P>
<P><STRONG>
</STRONG></P>
<BLOCKQUOTE><IMG SRC="../../gx/dennis/bbub.gif" alt="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
This is a classic FAQ. The BIOS standards for memory query
(Int 12h?) don't support the return of more than 64Mb of
RAM. There are a number of different mechanisms for doing
this on different chipsets, and some were "dangerous" (in
the sense that they might hang some systems with a different
API/BIOS). So, Linux didn't support automatic detection of
more than 64Mb on most systems until very recently
(2.0.36?).
</BLOCKQUOTE>
<BLOCKQUOTE>
You've always been able to over-ride this with a kernel
parameter. As you may know from my earlier articles or from
the LILO man pages you can pass parameters to the Linux
kernel using an append= directive in your <TT>/etc/lilo.conf</TT>
file (and subsequently runing <TT>/sbin/lilo</TT>, of course) or by
manually appending the parameters on the command line at the
LILO prompt (or on the LOADLIN.EXE command line).
</BLOCKQUOTE>
<BLOCKQUOTE>
To do this with <tt>lilo.conf</tt> you add lines of the form:
</BLOCKQUOTE>
<BLOCKQUOTE> <BLOCKQUOTE> <CODE>
append="mem=128M"
</CODE> </BLOCKQUOTE> </BLOCKQUOTE>
<BLOCKQUOTE>
... to each of the Linux stanzas to which you want this to
apply. (I'd leave one of them without it for the first try
so you have a working configuration into which you can boot
in case there's a problem with your system. I've heard of
some cases where users had to reduce their memory
configuration by 1Mb for odd reasons).
</BLOCKQUOTE>
<BLOCKQUOTE>
With the newer 2.0.36 and 2.1.x kernels you shouldn't
need to do this (they have new autodetection code that
should handle all of the common chipsets).
</BLOCKQUOTE>
<BLOCKQUOTE>
One trick for programmers --- if you want to ensure that
your code or distribution will run in limited memory
constraints you can do a quick test using a smaller
mem= parameter to force the kernel to run in less space
than it normally would.
</BLOCKQUOTE>
<BLOCKQUOTE>
WARNING: If you forget the trailing '<TT>M</TT>' the kernel load
will fail when it tries to allocate the specified amount
of RAM <EM>in bytes</EM>. (Don't do that!).
</BLOCKQUOTE>
<BLOCKQUOTE>
In any event you might want to check out some of the
FAQ's on Linux since I'm sure this is in a couple of them.
</BLOCKQUOTE>
<!-- sig -->
<!-- end 63 -->
<hr width="40%" align="center">
<!-- begin 60 -->
<H3 align="left"><img src="../../gx/dennis/qbubble.gif" height="50" width="60"
alt="(?) " border="0">
Using only 64Mb out of 128Mb Available
</H3>
<p><strong>From Terry Singleton on Fri, 18 Dec 1998
</strong></p>
<!-- ::
More on:
Using only 64Mb out of 128Mb Available
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
:: -->
<P><STRONG><IMG SRC="../../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Thanks Jim.I added the line as you suggested, however it did not seem to
<EM>take</EM> am I supposed to be it under the boot image section
itself? Memory is still 64000av.
</STRONG></P>
<BLOCKQUOTE><IMG SRC="../../gx/dennis/bbub.gif" alt="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Sorry, I should have been more detailed. You need
to add this <tt>append=</tt> directive to each of the stanzas to
which it applies. (You could have a couple of stanzas
that referred to reduced memory configuration if you were
a software developer, tester or reviewer so that you could
test a package's behaviour under varying memory constraints).
</BLOCKQUOTE>
<P><STRONG><IMG SRC="../../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
This is what I have:
</STRONG></P>
<pre><strong> boot=/dev/sda
map=/boot/map
install=/boot/boot.b
prompt
timeout=50
append="mem=128M"
image=/boot/vmlinuz-2.0.34-0.6
label=linux
root=/dev/sda1
initrd=/boot/initrd-2.0.34-0.6.img
read-only
</strong></pre><P><STRONG>
should it be:
</STRONG></P>
<pre><strong> boot=/dev/sda
map=/boot/map
install=/boot/boot.b
prompt
timeout=50
image=/boot/vmlinuz-2.0.34-0.6
label=linux
root=/dev/sda1
initrd=/boot/initrd-2.0.34-0.6.img
read-only
append="mem=128M"
</strong></pre><BLOCKQUOTE><IMG SRC="../../gx/dennis/bbub.gif" alt="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Yes.
</BLOCKQUOTE>
<BLOCKQUOTE>
(Also remember to re-run <TT>/sbin/lilo</TT> to read this
config file and build the new boot blocks and maps
therefrom).
</BLOCKQUOTE>
<BLOCKQUOTE>
Incidentally it would have been quicker and reasonably
safe (in this case) to just try the experiement. It
should have worked and you'd have gotten your answer
much quicker.
</BLOCKQUOTE>
<BLOCKQUOTE>
I can understand a degree of hesitation about experimenting
with the boot blocks and partition tables (a data structure
that's stored in the the same block as the MBR first stage
boot block). Obviously a mistake means that you can't
boot at all.
</BLOCKQUOTE>
<BLOCKQUOTE>
However, it's wise to have a backup <em>and a working rescue
floppy</em> and to practice using them before you make any
changes to your <TT>/etc/lilo.conf.</TT>
</BLOCKQUOTE>
<!-- sig -->
<!-- end 60 -->
<!--startcut ======================================================= -->
<P> <hr> <P>
<H5 align="center"><a href="http://www.linuxgazette.com/ssc.copying.html"
>Copyright ©</a> 1999, James T. Dennis
<BR>Published in <I>The Linux Gazette</I> Issue 36 January 1999</H5>
<P> <hr> <P>
<!-- ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: -->
<P align="center">
<table width="98%"><tr valign="center" align="center">
<td rowspan="3" colspan="6"><A HREF="../lg_answer36.html"><IMG
SRC="../../gx/dennis/answernew.gif"
ALT="[ Answer Guy Index ]"></A></td>
<TD><A HREF="./a.html">a</A></TD>
<TD><A HREF="./b.html">b</A></TD>
<TD><A HREF="./c.html">c</A></TD>
<TD><A HREF="./1.html">1</A></TD>
<TD><A HREF="./2.html">2</A></TD>
<TD><A HREF="./3.html">3</A></TD>
<TD><A HREF="./4.html">4</A></TD>
<TD><A HREF="./5.html">5</A></TD>
<TD><A HREF="./6.html">6</A></TD>
<TD><A HREF="./7.html">7</A></TD>
<TD><A HREF="./9.html">9</A></TD>
<TD><A HREF="./10.html">10</A></TD>
<TD><A HREF="./11.html">11</A></TD>
<TD><A HREF="./12.html">12</A></TD>
</tr><tr valign="center" align="center">
<TD><A HREF="./15.html">15</A></TD>
<TD><A HREF="./16.html">16</A></TD>
<TD><A HREF="./18.html">18</A></TD>
<TD><A HREF="./19.html">19</A></TD>
<TD><A HREF="./20.html">20</A></TD>
<TD><A HREF="./21.html">21</A></TD>
<TD><A HREF="./22.html">22</A></TD>
<TD><A HREF="./23.html">23</A></TD>
<TD><A HREF="./24.html">24</A></TD>
<TD><A HREF="./25.html">25</A></TD>
<TD><A HREF="./26.html">26</A></TD>
<TD><A HREF="./27.html">27</A></TD>
<TD><A HREF="./28.html">28</A></TD>
</tr><tr valign="center" align="center">
<TD><A HREF="./29.html">29</A></TD>
<TD><A HREF="./31.html">31</A></TD>
<TD><A HREF="./32.html">32</A></TD>
<TD><A HREF="./33.html">33</A></TD>
<TD><A HREF="./34.html">34</A></TD>
<TD><A HREF="./35.html">35</A></TD>
<TD><A HREF="./36.html">36</A></TD>
<TD><A HREF="./37.html">37</A></TD>
<TD><A HREF="./38.html">38</A></TD>
<TD><A HREF="./39.html">39</A></TD>
<TD><A HREF="./40.html">40</A></TD>
<TD><A HREF="./41.html">41</A></TD>
<TD><A HREF="./42.html">42</A></TD>
<TD><A HREF="./44.html">44</A></TD>
</tr><tr valign="center" align="center">
<TD><A HREF="./45.html">45</A></TD>
<TD><A HREF="./46.html">46</A></TD>
<TD><A HREF="./47.html">47</A></TD>
<TD><A HREF="./48.html">48</A></TD>
<TD><A HREF="./49.html">49</A></TD>
<TD><A HREF="./50.html">50</A></TD>
<TD><A HREF="./51.html">51</A></TD>
<TD><A HREF="./52.html">52</A></TD>
<TD><A HREF="./53.html">53</A></TD>
<TD><A HREF="./54.html">54</A></TD>
<TD><A HREF="./55.html">55</A></TD>
<TD><A HREF="./56.html">56</A></TD>
<TD><A HREF="./57.html">57</A></TD>
<TD><A HREF="./60.html">60</A></TD>
<TD><A HREF="./61.html">61</A></TD>
<TD><A HREF="./62.html">62</A></TD>
<TD><A HREF="./63.html">63</A></TD>
<TD><A HREF="./64.html">64</A></TD>
<TD><A HREF="./65.html">65</A></TD>
<TD><A HREF="./66.html">66</A></TD>
</tr><tr valign="center" align="center">
<TD><A HREF="./67.html">67</A></TD>
<TD><A HREF="./69.html">69</A></TD>
<TD><A HREF="./72.html">72</A></TD>
<TD><A HREF="./76.html">76</A></TD>
<TD><A HREF="./77.html">77</A></TD>
<TD><A HREF="./78.html">78</A></TD>
<TD><A HREF="./79.html">79</A></TD>
<TD><A HREF="./80.html">80</A></TD>
<TD><A HREF="./81.html">81</A></TD>
<TD><A HREF="./82.html">82</A></TD>
<TD><A HREF="./84.html">84</A></TD>
<TD><A HREF="./85.html">85</A></TD>
<TD><A HREF="./86.html">86</A></TD>
<TD><A HREF="./87.html">87</A></TD>
<TD><A HREF="./91.html">91</A></TD>
<TD><A HREF="./94.html">94</A></TD>
<TD><A HREF="./95.html">95</A></TD>
<TD><A HREF="./96.html">96</A></TD>
<TD><A HREF="./97.html">97</A></TD>
<TD><A HREF="./98.html">98</A></TD>
</tr></table>
</P>
<P> <hr> <P>
<!-- ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: -->
<A HREF="../lg_toc36.html"
><IMG SRC="../../gx/indexnew.gif" ALT="[ Table Of Contents ]"></A>
<A HREF="../../index.html"
><IMG SRC="../../gx/homenew.gif" ALT="[ Front Page ]"></A>
<A HREF="../lg_bytes36.html"
><IMG SRC="../../gx/back2.gif" ALT="[ Previous Section ]"></A>
<A HREF="../larriera.html"
><IMG SRC="../../gx/fwd.gif" ALT="[ Next Section ]"></A>
<!-- ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: -->
</BODY></HTML>
<!--endcut ========================================================= -->
|
