Its zero-length files are neither binary nor text,
yet you can examine and display them
Under Linux, everything is managed as a file;
even devices are accessed as files (in the /dev directory).
Although you might think that “normal” files are either text or binary (or possibly device or pipe files),
the /proc directory contains a stranger type:
virtual files.
These files are listed, but don’t actually exist on disk;
Although almost all the files are read-only,
a few writable ones (notably in /proc/sys)
allow you to change kernel parameters.
(Of course, you must be careful if you do this.)
The numbered directories correspond to each running process;
a special self symlink points to the current process.
Some virtual files provide hardware information, such as
/proc/cpuinfo,
/proc/meminfo,
/proc/interrupts.
Others give file-related info, such as
/proc/filesystems
/proc/partitions.
The files under /proc/sys are related to kernel configuration parameters
/proc/cmdline:
Shows the parameters that were passed to the kernel at boot time.
/proc/dma:
Shows the Direct Memory Access channels in use.
the numerical named directories
represent all running processes.
When a process ends,
its /proc directory disappears automatically
cmdline:
Contains the command that started the process, with all its parameters.
cwd:
A symlink to the current working directory (CWD)for the process;
exe links to the process executable,
and root links to its root directory.
environ:
Shows all environment variables for the process.
fd:
Contains all file descriptors for a process,
showing which files or devices it is using.
maps, statm, and mem:
Deal with the memory in use by the process.
stat and status:
Provide information about the status of the process,
but the latter is far clearer than the former.
if you want to program a better-looking top,
all the needed information is right at your fingertips.
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1. E (归一化坐标对进行计算) t ^ R 为3*3的矩阵, 因为R,t共有6个自由度,又因为单目尺度等价性,所以实际上E矩阵共有5个自由度。因此至少需要5个点对来求解。
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3*3且自由度为7的矩阵kF也为基础矩阵&#x…