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SPG - Sync Pulse Generator

Master Clock/SPG 

Commercial broadcast systems have many individual sources and destinations, those generate audio  and video signal. In such multi sources/destinations environment every individual device gives outputs in an asynchronous way. This may result jerked or ambiguous frame in raster. After the generation of the video signal it needs a reference (path) to flow. If the signal finds no path the video signal may give information to the TV receiver other than the desired one. In multi sources destination environment it is desired for all signals to be synchronous with each other. For that purpose master clock or SPG (synch pulse generator) is used. It provides reference signal to all of the station equipments. It also generates the time code. For sooth and repayable flow the reference signal (black burst signal, colour burst signal) is provided. With respect to this signal the base-band signal flows to its desired destination without being disturbed. SPG section does that every thing. The master clock portion actually provides the TC (time code) for making all the equipment synchronized. This time code is generated by the satellite. A GPS (global positioning system) antenna receives the reference signal and the master clock portion generates the time code scanning the receiving signal. This time code is thrown to the GPS clock, VTRs. Server system etc.



 Figure : Time code and reference signal system block

There are  many professional SPG of various brand in broadcast market. Among those 5600MSC and 5601MSC of Evertz brand is popular.

         Figure: Evertz 5600MSC and 5601MSC SPG

Bangladeshi TV Channel Downlink Parameter - 2019

Now in Bangladesh approximately more than 25 private satellite TV channel is being onaird. Most of them are standard definitation (SD). But newly setup TV channels are high definitation (HD,1080i). All TV station using Apster-7 satellite for their main uplink purpose. Only the national TV channel (BTV) downlink polarization is Vartical (V). All the private TV station downlink polarization is Horizantal (H).

To receive the signal of the TV, we need to know the downlink parameter of that specefic TV station. Here in the document, has the downlink parameter of all private TV channels.
But the downlink parameter is changed according to the recruitment of the TV station. So keep in touch to get the update information about the downlink information.    











   

Miscellaneous short note on Linux. Part -5

# Server administrator frequently list directories and stored both errors and standard output into a file which can be process later.

# A filter in a pipe is an output of one command with serves as i/p to the next

#The grep command can be used to find strings and values in a text document.

# cat fruits | grep –V a | sort –r --- Here cat command display the file fruits. This This result would be outputted to the grep command which will not search for the string which will not contain character a. Now output of this command would be worked on by the sort command to display the result in the reverse to display the result in the reverse order. This process is called filter.

# PS --- Process Status

# PS is similar to the task manager of windows.

# ps ux --- It will provide all the information about process and program running in system           

# less, pg and more commands are used for the dividing a long file into readable file.

# regular expression ---- tr, sed, vi, grep

# Interval regular expression --- Number of occurrences of a charter in a string

# Regular expression also called “regexp” or “regex”

# interval regular expression {n,m} --- Matches the preceding character appering “n”  times but not more than “m”


# The brace {} expression is used to generate strings. It helps in creating multiple strings out of one.

Miscellaneous short note on Linux. Part -4

# uptime --- It shows since how long system is running and the number of user are  currently logged in and also displays load average for 1, 5 and 15 minutes intervals

# Three types of owner of file or directory
(i)                 User or creator of the file
(ii)               Group [All user belonging in the group have the same file permission]
(iii)             Other [Any other user who has access permission to a file. Other does not own the file not belong to the group]

 # ls –l and ls –la are not same.


# Using the “pr” command you can format and print a file directly from the terminal. The formatting you do on the files does not affect the file content.

# standard input (stdin) device is the keyboard

# standard output (stdout)  device is the monitor

# “>” symbol is used for output (stdout) redirection to another file. If the file with the same name exist then the previous file will be over written.

# echo hello > listing --- listing life content will be hello

# “>>” symbol is used to add content to the existing file. It will not overwrite the content of the existing file.

# “<” symbol is used for input (stdin) redirection.

# every file has a number called FD.

# whenever you execute a program or command, three files are always open.
(i)                 Standard input --- FD 0
(ii)               Standard output --- FD 1
(iii)             Standard error --- FD 2

# “>&” which write the output from one file to the input of another file.

# Each file in linux has a corresponding file descriptor associated with it.

# You can redirect error using it’s corresponding file descriptor 2

# find --- To search in a specific directory for a file 

Environment Variable and Communication in Linux


Environment Variable
Platform = Operating system + Processor
# echo $ <variable> --- To determine the value of the <variable>
# echo $ path --- This variable contains a colon (:) separated list of directories in which your system looks for executable files.
# echo $ user --- Give us the name of the user.
# Variable are case sensitive
# echo $ home --- Show the default path of the user home directory
# env --- Show all the environment variable
#Usually variable are created in the upper case
# To create new variable $newvariable = value123
# unset <variable_name> --- To delete variable
# Environment variable govern behavior of program in your operating system
# export variable = value --- To set value of an environment variable


Communication in Linux
# FTP is used for login and establishing a connection in the remote computer.
# ftp <ip-address or host-name> ---- to login in the remote host
# After login into the remote host via ftp the following option may be used
   dir --- Display files in the current directory of remote computer
   cd “dirname” --- Change directory into the “dirname” on remote computer
   put “file” --- Upload “file” from local to remote computer
   get “file” --- Download “file” from remote to local computer

  quit --- logout

Telnet and SSH (Secure Shell) in Linux


Telnet
# Telnet is used to connect to a remote linux computer
# Run programs remptely and conduct administration
# Telnet is similar to remote desktop found in windows machine
# telnet <ip-address or host-name> --- To login into the remote computer using telnet
# Telnet is obsolete over the years





SSH (Secure Shell)

# SSH is more secure than telnet
# It is used securely connect to the remote computer
# SSH is widely used by the system administrator to login remote computer
# ssh <user-name>@ip-address or hostname ---
# dir --- This will list all the directory content in the current directory
# To logout from ssh write “exit”
# ftp is preferred protocol for sending and receiving large files. You can establish a ftp connection with a remote host and then use command for uploading, downloading files, checking files and browsing them

# ssh is replacement of telnet

Sample Question of RHCSA (EX200) --- 6

QUESTION NO – 1: Configuring Anonymous FTP Server
Configure FTP access on your system such that clients should have anonymous FTP access to your machine using the url ftp://station.domain2.example.com.

QUESTION NO – 2: User-Group Administration
Create the following users, groups and group memberships:
- A group named sysmgrs
- A user natasha who belongs to sysmgrs as a secondary group
- A user harry who also belongs to sysmgrs as a secondary group
- A user robert who does not have access to an interactive shell on the system and who is not a member of sysmgrs.
- The users natasha, harry and robert will all use tritebam as their login password.

QUESTION NO – 3: User of Specific UID
Create an user lorent whose user ID will be 1900.

QUESTION NO – 4: System Synchronization
Syncronise your system time with NTP server. Use host.domain2.example.com as your NTP server.

QUESTION NO – 5: LDAP Authentication
Authenticate with the LDAP server located in your domain: domain2.example.com. Configure your system to get information about network users from a LDAP directory Server available to all machine in the classroom. Here is the information that has been provided to you about LDAP.
- Search Base DN: dc=domain2,dc=example,dc=com
- LDAP Server: host.domain2.example.com
- CA Certificate:
http://host.domain2.example.com/pub/EXAMPLE-CA-CERT

QUESTION NO – 6: Configuring autofs
Configure your server to automatically mount the home directory of your LDAP based while logging in as a domain user.
- host.domain2.example.com (172.24.2.254)
- NFS server exports /netdir/ldapuser2 to your system
- LDAP user's home directory is host.domain2.example.com:/netdir/ldapuser2. Ldapuser's home directory should be automounted locally beneath at /netdir/ldapuser2.
- While login with ldapuser2 then only home directory should accesible from your system that ldapuser2 has.


QUESTION NO – 7:  Logical Volume Mounting
 - Create a logical volume qa of 60 extents. The logical volume qa will be under volume group qagroup. The extent size will be 16MiB. Mount the logical volume to /test. Be confirm it will be vfat format and use geografical information.


Sample Question of RHCSA (EX200) --- 5

QUESTION NO – 1
Use radiowits as your login password as root user. Your station ID is 2. Your machine will be a member of the domain2.example.com. All systems in the domain2.example.com domain are in 172.24.2.0/255.255.255.0 subnet and all systems in that subnet are in domain2.example.com. Configure your network with static requirements. Use terminal for any kind of command executes.
Hostname = station.domain2.example.com
IP Address = 172.24.2.20
Subnet Mask = 255.255.255.0
Default Gateway = 172.24.2.254
DNS Server = 172.24.2.250


QUESTION NO – 2: Testing Network Configuration
     - Ping your own IP address successfully
     - Ping your default gateway address successfully
     - Ping your nameserver address successfully
     - Digonose your nameserver
     - Ping your own host using hostname
     - Ping your nameserver using hostname
     - Ping your default gateway system using hostname


QUESTION NO – 3: YUM Configuration
Install rpm on the examination system using the following source for the Installation media: NFS        host.domain2.example.com:/var/ftp/pub/Packages

Once your system is installed, the distribution is available via YUM:
YUM ftp://host.domain2.example.com/pub/rhel6        /dvd/Packages


QUESTION NO – 4: Resizing Logical Volume
Resize the logical volume vo into 250M from the current size and mount the logical volume to a mount point /vol.
The extended partition size must be within approximately 230MB to 270MB and useable.


QUESTION NO – 5: Swap Partitioning
Create a 100MB partition which will be formated with swap file system and added after next boot. 


QUESTION NO – 6: Updating Kernel
Install the appropriate kernel update from ftp://host.domain2.example.com/pub/update. The following criteria must also be met:

       (1) The updated kernel will be the default kernel when the system is rebooted
       (2) The original kernel will be available and bootable on the system.


QUESTION NO – 7: Basic Partitioning & Mounting
Create a 100MB new partition and should be mounted under /next as ext4 type.


QUESTION NO – 8: Directory Sharing through NFS
The machine must export /shared to the domain2.example.com network. Test the below command to check the exported share for local host.


                                                                                                       

Sample Question of RHCSA (EX200) --- 4

QUESTION NO – 1: Main Web-hosting
Implement a web server for the site http://station.domain2.example.com, then perform the following steps:

     - Download ftp://host.domain2.example.com/pub/rhce/station.html
     - Rename the downloaded file to index.html
     - Copy this index.html to the document root of your web server
     - Do not make any modifications to the content of index.html

QUESTION NO- 2: Ownership & Permission
Copy the file /etc/fstab to /var/tmp/fstab. Configure the permissions of /var/tmp/fstab so that:
      - The file /var/tmp/fstab is owned by the root user.
      - The file /var/tmp/fstab belongs to the group root.
      - The file /var/tmp/fstab should not be executable by anyone.
      - The user natasha is able to read and write /var/tmp/fstab.
      - The user harry can neither write nor read /var/tmp/fstab.
      - All other users (current or future) have the ability to read /var/tmp/fstab.

QUESTION NO – 3: Adding Cron Job
The user harry must configure a cron job that runs daily at 14:15 local time and executes /bin/echo hello.

QUESTION NO – 4: Advanched Permission
Create a collaborative directory /shared/sysmgrs with the following characteristics:

- Group ownership of /shared/sysmgrs is sysmgrs
- The directory should be readable, writable, and accessible to members of sysmgrs, but not to any other user.
- Files created in /shared/sysmgrs automatically have group ownership set to the sysmgrs Group.


Sample Question of RHCSA (Ex200) --- 3

Question 1 of 14
Configure a machine with following properties
(i) IP: 172.24.9.10
(ii) Subnet Mask: 255.255.255.0
(iii) Default Geatway: 172.24.254.254
(iv)  Hostname: system1.group10.example.com
(v) System Root Password : trootent

Question 2 of 14
Create a repository where repository access location is content.group.example.com/rhel7/x86_64/dvd

Question 3 of 14
Create an user with natasha with ID 2040

Question 4 of 14
Create three user named "neo", "jenny" and "joe" and a group called "office". Jenny and neo's seceondary group is office. Joe user has no interrective shell.

Question 5 of 14
Install a service
Configure ftp service for the network  group10.example.com

Question 6 of 14
Reduce home partition to 1500 MB from the current size. Current status of home partition is 2048 MB and partition format is ext4.

Question 7 of 14
ACL: Copy the /etc/passwd file to /var/tmp. Configure the permission as /var/tmp/passwd file is own by the root user. It should not be executable by anyone.
User "Andrew" is able to read and write the file. User susan nither read nor write the file. All other user have the ability to read the file.

Question 8 of 14
Make a schedule task to run the command /bin/shell to 26th June at 12:30 am. Make sure Jenny cann ot make any schedule in the system.

Question 9 of 14
Schedule task: User neo will configure a cron schedule that runs daily at 15:25 local time and execute /bin/echo I got the RHCE certificate.

Question 10 of 14
Find all file owned by Jenny and copy files into /root/found.

Question 11 of 14
Create a swap partition 1GB persistantly

Question 12 of 14
Create a volume group named depertment with 32MB PE and a logical volume named engineering woth 20 LE and mount it under /testing directory.

Question 13 of 14
LVM extend: Extend /testing directory upto 300MB

Question 14 of 14

Create a backup file named /root/backup.tar.bz2 which contains the content of /user/local. Tar must use bzip2 compression.   

Sample Question of RHCSA (EX200) --- 2

QUESTION NO: 1
Configure your Host Name, IP Address, Gateway and DNS.
Host name: station.domain40.example.com
IP Address:172.24.40.40/24
Gateway:172.24.40.1
DNS: 172.24.40.1

QUESTION NO: 2
Add 3 users: harry, natasha, tom. The requirements: The Additional group of the two users: harry, Natasha is the admin group. The user: tom's login shell should be non-interactive.

QUESTION NO: 3
Create a catalog under /home named admins. Its respective group is requested to be the admin group. The group users could read and write, while other users are not allowed to access it. The files created by users from the same group should also be the admin group.


QUESTION NO: 4
Configure a task: plan to run echo hello command at 14:23 every day.

QUESTION NO: 5
Find the files owned by harry and copy it to catalog: /opt/dir

QUESTION NO: 6
Find the rows that contain abcde from file /etc/testfile, and write it to the file/tmp/testfile, and the sequence is requested as the same as /etc/testfile.


QUESTION NO: 7
Create a 2G swap partition which take effect automatically at boot-start, and it should not affect the original swap partition.

QUESTION NO: 8

Create a user named alex and the user id should be 1234, and the password should be alex111. 

Sample Question of RHCSA (EX200) --- 1

Question 1 of 14
Create two users: john with uid/gid equal to 2000, password 12345678 and davis with uid/gid equal to 3000, password 87654321. Make davis‘account validity stopping in one month.

Question 2 of 14
Allow davis (and only davis) to get full access to john‘s home directory.

Question 3 of 14
Create a directory named /common. Allow john and davis to share documents in the /common directory using a group called team. Both of them can read, write and remove documents from the other in this directory but any user not member of the group can’t.

Question 4 of 14
Create a xfs file system on a new logical volume of 100MB called lv_xfs. Mount it permanently with uuid under /xfs.

Question 5 of 14
Extend the existing xfs file system to a total size of 200MB and add a label called myFS.

Question 6 of 14
Write a Bash script called prog.sh in the /root directory that creates 40 files of 2MB each with the fallocate command in the mounted /xfs directory. Each file has got a name as follows: .file_N where N is a number from 1 to 40.

Question 7 of 14
Create an ext4 file system on a new logical volume of 100MB called lv_ext4. Mount it permanently under the /ext4 directory. Copy the files previously created into this new space.

Question 8 of 14
Assign the same SELinux contexts used by the home directories to the /xfs directory permanently.

Question 9 of 14
Configure a virtual console.

Question 10 of 14
Create a logical volume of 200MB called lv_swap2 and add it permanently to the current swap space.

Question 11 of 14
Install the Apache package. Allow it to get documents stored on NFS mounted directories.

Question 12 of 14
Create a cron job running as root, starting at 11PM every day and writing a report on daily system resource consumption in the /var/log/consumption.log file.

Question 13 of 14
Set the default target to boot into X Window level (previously level 5).

Question 14 of 14

Change the hostname to mycentos.example.com

Disk Free (DF) Utility in Linux System




Disk Free (DF) Utility


# df --- Show the used and available disk space 

# free –m --- Show free and used RAM in megabyte

#free –g --- Show free and used RAM in giga bytes 

# bg --- To send a process to back ground

# fg --- To run a stopped process in the back ground


# top --- Details of all active process 

# ps --- Give the status of a process running for a user

# ps <PID_number> --- Give the status of a particular process 

# pidof  <process_name> --- Give the process ID (PID) of a process

# kill <PID_number> --- kill a process

# nice --- start a process with a given priority


# renice --- Change priority of an already running process

# df --- give free hard disk of your system

# free --- Tell the free RAM of your system