RCS file: cleanup.c,v
Working file: cleanup.c
head: 1.3
branch:
“logcleanup” 58L, 1784C                                                                                                            32,1          Top
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CS file: init.c,v
Working file: init.c
head: 1.2
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total revisions: 2;     selected revisions: 2
description:
alloc_chrdev is done for registring the device
kmalloc is done to allocate memory to device
then memset is done
before kmalloc print major and minor no that are present in dev
now initilization is done means kernel provide memory
cdev_add is done to add on something
now again print major and minor no that are nor present in c_dev which is within struct sculldev
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revision 1.2    locked by: root;
date: 2014/05/08 10:06:58;  author: root;  state: Exp;  lines: +2 -3
if number of devices are more in number then use for loop
module_param is used to pass command line arguments that is number of nodes is passed by user on the shell
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revision 1.1
date: 2014/05/08 10:00:06;  author: root;  state: Exp;
Initial revision
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RCS file: init.c,v
Working file: init.c
head: 1.2
branch:
“loginit” 58L, 2084C                                                                                                               1,0-1         Top
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RCS file: dec.h,v
Working file: dec.h
head: 1.1
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description:
we extern node number
dev_t dev
struct sculldev *sculldev
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revision 1.1    locked by: root;
date: 2014/05/08 10:00:06;  author: root;  state: Exp;
Initial revision
=============================================================================

RCS file: dec.h,v
Working file: dec.h
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description:
we extern node number
dev_t dev

struct sculldev *sculldev
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revision 1.1    locked by: root;
date: 2014/05/08 10:00:06;  author: root;  state: Exp;
Initial revision
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RCS file: file_op.h,v
Working file: file_op.h
head: 1.1
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description:
struct file_opeartion is created where mapping of open and release functon is done
include this in init functin
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revision 1.1    locked by: root;
date: 2014/05/08 10:20:54;  author: root;  state: Exp;
Initial revision
=============================================================================

RCS file: file_op.h,v
Working file: file_op.h
head: 1.1
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total revisions: 1;     selected revisions: 1
description:
struct file_opeartion is created where mapping of open and release functon is done
include this in init functin
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RCS file: header.h,v
Working file: header.h
head: 1.2
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description:
include header files that are needed in this program
struct sculldev structure is included here
that include c_dev
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revision 1.2    locked by: root;
date: 2014/05/08 10:20:29;  author: root;  state: Exp;  lines: +1 -0
defination of scullopen and scullrelease is given here
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revision 1.1
date: 2014/05/08 10:00:06;  author: root;  state: Exp;
Initial revision
=============================================================================

RCS file: header.h,v
Working file: header.h
head: 1.2
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1,0-1         Top
total revisions: 2;     selected revisions: 2
description:
include header files that are needed in this program
struct sculldev structure is included here
that include c_dev
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revision 1.2    locked by: root;
date: 2014/05/08 10:20:29;  author: root;  state: Exp;  lines: +1 -0
defination of scullopen

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shell is a program that takes command typed by the user and calls operating system to run those commands. Commonly used commands in shell script are—

1. unset —-used to delete variable

2. echo——used for printing

3. read——preform the function of scanf

BLOCK is define as-
struct_msg
{
unsigned long type;
char *payload;
};
where type is process pid
payload is message.
In message queues, both sender and receiver are independent of each other.
MSGMAX——-maximum size of payload
MSGMNB——-maximum number of blocks

1. msgget–
int msgget(key_t key,int msgflg);
2. msgctl—-
int msgctl(int msqid,
int command,
struct msqid_ds *buf);
commands are——
IPC_STAT—structure initialized
IPC_SET—-assigne value to message queqe
IPC_RMID—delete message queue
3. msgsend
int msgsend( int msqid,
const void *msg_ptr,
size_t msg_sz,
int msgflg,);

where struct is a keyword.
name is a name of user define data type.
struct name variable is used to define variable globally.
EXAMPLE:
struct distance
{
int feet;
float inches;
};
struct distance d;