Homework 1.


Due by 11:59pm EST on September 30, 2004.


PART A: (50 points)

 1.   (5x3 = 15 points)

Log into the linuxserver linux1@gl.umbc.edu.
 
 a) What operating system does it run? What is the kernel version it runs?
OS = Linux
Kernel = 2.4.26 w/ SMP

bash-2.05a$ uname -a
Linux linux1.gl.umbc.edu 2.4.26 #1 SMP Thu Apr 22 13:38:42 EDT 2004 i686 unknown


 b) Is this a Batched system?
Yes this is a batched system. It has the memory layout of a batched system where
the OS is seperated from user programs.
 
 c) Is this a Multiprogrammed system?
Yes this is a multiprogrammed system.  It has many processes (programs) running (or
waiting to run [see time-sharing below]).
 
 d) Is this a Time-sharing system?
Yes this is a time-sharing system.  Processor/resource time is divided between
many processes.

 
 e) Is this a Multiprocessor system?
I believe this is NOT a multiprocessor linux system.  The output below 
shows that it is a HyperThreaded P4/Xeon class processor.  This is why
there are 2 CPU's listed.  But hyperthreading is NOT true multiprocessor,
there is still only 1 physical processor and 1 core.

Output:
[sshimko1@linux1 ~]$ cat /proc/cpuinfo
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 15
model           : 2
model name      : Intel(R) Xeon(TM) CPU 3.06GHz
stepping        : 9
cpu MHz         : 3052.254
cache size      : 512 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 pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe cid
bogomips        : 6094.84

processor       : 1
vendor_id       : GenuineIntel
cpu family      : 15
model           : 2
model name      : Intel(R) Xeon(TM) CPU 3.06GHz
stepping        : 9
cpu MHz         : 3052.254
cache size      : 512 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 pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe cid
bogomips        : 6094.84


2. What are system calls? What is their purpose? How are they handled?    (15 points)
The method user processes use to request that the kernel perform privleged 
operations.  It is handled like a software interrupt (typically 0x80).  
 

3. Problems 2.5 on pages 52-53 in the text book.    (10 points)
a) privileged
b) unprivileged
c) privileged
d) privileged
e) privileged


4. Problem 4.6 on page 127 from your text book.   (10 points)
 


PART B: (50 points) 

Familiarize yourself with the /proc filesystem in the Linux OS (eg at a minimum look at the man pages for proc). Log on to linux.gl.umbc.edu and explore the /proc directory. This directory provides an easy way to get a lot of information about the current system. 
 
 The file /proc/meminfo contains information about the free and used memory in the system. The unix command "free" uses this file to generate its output. Write your own version of the command "free" in C. Run the command "free" at your promt to see the sample of what the output should look like.