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