Which four statements are true about the /proc file system?

The /proc file system is a pseudo-file system, which is used as an interface to kernel data
structures. Which four statements are true about the /proc file system?

A.
The /proc file system contains a numerical subdirectory for each running process.

B.
The /proc file system contains a hierarchy of special files that represent the current state of the
kernel.

C.
The /proc file system has to be mounted by the system administrator after a reboot.

D.
The /proc/cpuinfo virtual file identifies the type of processor used by your system.

E.
The /proc directory contains information about system hardware and any running processes.

F.
The files in the /proc directory are read-only system files that cannot be changed.

Explanation:
*The /proc file system exists in slightly different variations on Linux and the Solaris
OS. On both systems, /proc is a directory containing files whose names are the process IDs of the
current active processes on the system(A). Each PID-named file is in turn a directory. /proc on
Linux has various other directories besides processes. Most of these deal with processors,
devices, and statistics on the system. On Linux, one looks in /proc to find information about
processes, processors, devices, machine architecture, and so on(E).
*The /proc is a virtual file system that contains files that show the status of the Linux operating
system kernel. Most of the files have a size of 0 bytes, but they actually contain a large amount of
data. The timestamps of these virtual files changes as the contents of the files are updated by the
OS.
*The following virtual files provide an indication, at the moment they are being viewed, about the
system hardware:
n /proc/partitions: Gives the size and name of partitions
n /proc/meminfo: Memory statistics and segment sizes
n /proc/mounts: List of the mount points
n /proc/uptime: Uptime of the system
n /proc/interrupts: List of interrupts on the system
D:The contents of the files can be seen with the classical command cat, thereby viewing the
information of the CPU.
linux-mlpb:~ # cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 9
model name : Intel(R) Pentium(R) M processor 1700MHz
stepping : 8
cpu MHz : 1694.501
cache size : 1024 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no

coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 2
wp : yes
flags : fpu vme de pse tsc msr mce cx8 apic sep mtrr pge mca cmov pat clflush dts acpi mmx fxsr
sse sse2 up pebs bts
bogomips : 3408.43
clflush size : 64
linux-mlpb:~ # cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 9
model name : Intel(R) Pentium(R) M processor 1700MHz
stepping : 8
cpu MHz : 1694.501
cache size : 1024 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 2
wp : yes
flags : fpu vme de pse tsc msr mce cx8 apic sep mtrr pge mca cmov pat clflush dts acpi mmx fxsr
sse sse2 up pebs bts
bogomips : 3408.43
clflush size : 64