3 cons \- console, clocks, process/process group ids, user, null, reboot, etc.
33 The console device serves a one-level directory
34 giving access to the console screen and
35 miscellaneous information.
43 causes the characters to be printed on the console screen. Console
44 input is handled by a different program (see
49 file contains a textual representation of the operating system's version and parameters.
50 At the moment, it contains one field: the 9P protocol version, currently
55 file contains a copy of the kernel configuration file used to build the kernel.
59 file holds the last 16 kilobytes of output written to the console
60 by the kernel's print statements or by processes writing to
62 It is useful for retrieving boot messages once the boot
67 file may be read to receive a copy of the data written
68 to the console by the kernel's print statements or by processes
71 Only data written after the file is opened is available.
72 If the machine's console is a serial line, the data is sent both to the
75 if its console is a graphics screen, the data is sent either to the
79 (It is advisable not to open
81 on terminals until you have started
86 file throws away anything written to it
87 and always returns zero when read.
91 file is a read-only file that produces an infinite stream of zero-valued bytes when read.
95 file contains, one per line, a listing of the drivers configured in the kernel, in the format
103 file contains the name of the authentication domain that
104 this host belongs to; see
106 Only the user named in
112 file contains the name of the user that owns the console device files.
113 The hostowner also has group permissions for any local devices.
117 return a stream of random numbers. The numbers are
118 generated by a low priority kernel process that loops
119 incrementing a variable. Each clock tick the variable
120 is sampled and, if it has changed sufficiently, the last
121 few bits are appended to a buffer. This process is inefficient
122 at best producing at most a few hundred bits a second.
125 should be treated as a seed to
126 pseudo-random number generators which can produce a faster
133 causes the system to shutdown and, if
138 loads the named kernel image and restarts,
139 preserving the kernel configuration in
147 activates the remote kernel debugger (see
150 owner has the ability to open this file.
153 is a binary interface that provides
154 the same information as
158 and also controls clock frequency and clock trim.
159 All integers read or written from
161 are in big endian order.
162 Unlike the other files, reads and writes do not affect
163 the offset. Therefore, there is no need for a seek
164 back to zero between subsequent accesses.
167 returns 24 bytes, three 8 byte numbers, representing nanoseconds
168 since start of epoch, clock ticks, and clock frequency.
172 is a message with one of 3 formats:
173 .IP "\f5n\fP<8-byte \f2time\fP>" 1.2i
174 set the nanoseconds since epoch to the given
176 .IP "\f5d\fP<8-byte \f2delta\fP><4-byte \f2period\fP>" 1.2i
177 trim the nanoseconds since epoch by
182 .IP "\f5f\fP<8-byte \f2freq\fP>" 1.2i
183 Set the frequency for interpreting clock ticks to be
187 The rest of the files contain (mostly) read-only strings.
188 Each string has a fixed length: a
190 of more than that gives a result of that fixed length (the result does not
191 include a terminating zero byte);
194 of less than that length leaves the file offset so the
195 rest of the string (but no more) will be read the next time.
196 To reread the file without closing it,
198 must be used to reset the offset.
199 When the file contains numeric data
200 each number is formatted in decimal.
201 If the binary number fits in 32 bits, it is formatted as an
202 11 digit decimal number with
203 leading blanks and one trailing blank; totaling 12 bytes.
205 is formatted as 21 digit decimal numbers with leading blanks and one
206 trailing blank; totaling 22 bytes.
210 file holds six 32-bit numbers, containing the time in milliseconds
211 that the current process has spent in user mode, system calls,
212 real elapsed time, and then the time spent, by exited children and their descendants,
213 in user mode, system calls, and real elapsed time.
217 file holds one 32-bit number representing the seconds since start of epoch
218 and three 64-bit numbers, representing nanoseconds since
219 start of epoch, clock ticks, and clock frequency.
221 A write of a decimal number to
223 will set the seconds since epoch.
227 file holds the textual name of the machine, e.g.
233 file holds 10 numbers:
234 processor number, context switches, interrupts, system calls, page faults,
235 TLB faults, TLB purges, load average, idle time and time spent servicing interrupts.
236 The load average is in units of milli-CPUs and is decayed over time;
237 idle time and interrupt time are percentage units;
238 the others are total counts from boot time.
239 If the machine is a multiprocessor,
241 holds one line per processor.
244 resets all of the counts on all processors.
248 device holds a text block giving memory usage statistics:
256 \fIa\fP/\fIn\fP/\fIm\fP kernel malloc
257 \fIa\fP/\fIn\fP/\fIm\fP kernel draw
260 These are total memory (bytes), system page size (bytes),
261 kernel memory (pages), user memory (pages), swap space (pages),
262 kernel malloced data (bytes), and kernel graphics data (bytes).
270 For kernel malloc and kernel draw,
272 indicates the current allocation in bytes.
273 These numbers are not blank padded.
275 To turn on swapping, write to
277 the textual file descriptor number of a file or device on which to swap.
283 will inevitably cause the front to fall off.
285 The other files served by the
287 device are all single numbers:
296 parent's process number
306 .B /sys/src/9/port/devcons.c
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