IP - Ingress Protection Rating

IP - Ingress Protection rating is used to specify environmental protection - electrical enclosure - of Electrical Equipment

Ingress Protection (IP) ratings are developed by the IEC (International Electrotechnical Commission) and are most heavily used in Europe and Asia, with some adherents in North America as well. 

The IP rating normally has two (or three) numbers:

Ø  A two-digit number established by the International Electro Technical Commission, is used to provide an Ingress Protection rating to a piece of electronic equipment or to an enclosure for electronic equipment.

Ø  The protection class after EN60529 are indicated by short symbols that consist of the two code letters IP and a code numeral for the amount of the protection.

IP TABLE:

IP..	First digit: Ingress of solid objects	Second digit: Ingress of liquids
0	No protection	No protection
1	Protected against solid objects over 50mm e.g. hands, large tools.	Protected against vertically falling drops of water or condensation.
2	Protected against solid objects over 12.5mm e.g. hands, large tools.	Protected against falling drops of water, if the case is disposed up to 15 from vertical.
3	Protected against solid objects over 2.5mm e.g. wire, small tools.	Protected against sprays of water from any direction, even if the case is disposed up to 60from vertical.
4	Protected against solid objects over 1.0mm e.g. wires.	Protected against splash water from any direction.
5	Limited protection against dust ingress. (no harmful deposit)	Protected against low pressure water jets from any direction. Limited ingress permitted.
6	Totally protected against dust ingress.	Protected against high pressure water jets from any direction. Limited ingress permitted.
7	N/A	Protected against short periods of immersion in water.
8	N/A	Protected against long, durable periods of immersion in water.
9k	N/A	Protected against close-range high pressure, high temperature spray downs.

Ø  For enclosures, the typical “waterproof” IP ratings are IP67, IP66 and IP65 enclosures.  The chart below gives the specifics of what these ratings mean and how they are measured.

         

IP Rating	Protection	Description	Test Method
IP65 Enclosures	Able to protect against water jets	Water projected by a nozzle (6.3 mm) against enclosure from any direction shall have no harmful effects.	Test duration: at least 15 minutes
			Water volume: 12.5 litres per minute
			Pressure: 30 kPa at distance of 3 m
IP66 Enclosures	Able to protect against powerful water jets	Water projected in powerful jets (12.5 mm nozzle) against the enclosure from any direction shall have no harmful effects.	Test duration: at least 3 minutes
			Water volume: 100 litres per minute
			Pressure: 100 kPa at distance of 3 m
IP67 Enclsoures	Able to protect against Immersion up to 1 m	Ingress of water in harmful quantity shall not be possible when the enclosure is immersed in water under defined conditions of pressure and time (up to 1 m of submersion).	Test duration: 30 minutes
			Immersion at depth of at least 1 m measured at bottom of device, and at least 15 cm measured at top of device

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අපේ ඇස්වලට පෙනි පෙනී අපි නොදකින Gmail Inbox එකේ TAB වල ඇති සියලුම Email එකවර Delete කිරීම

දැන් Google සමාගම විසින් Gmail Inbox එක modify කරලයි තියෙන්නෙ ඒකෙ Primary, Social, Promotions, updates කියලා tabs වගයක් තියෙනවා‍. මට තිබුන ලොකුම අවුල තමයි මේ Social කියන TAB එක Facebook එකෙන්  එන email notifications වලින් පිරිලා තැබුනා. නමුත් මේවා එකෙන් එක Delete කරන එකනම් සෑහෙන වදයක් ඒකට පොඩි විසදුමක් තමයි අද මම කියන්න යන්නෙ.

ඒත් මේ කියන්න යන්නේ අමුතු දෙයක් ගැන නම් නෙවෙයි.  හැමෝටම පේන්න තියෙන ඒත් අවධානය යොමු නොවුණු පුංචි තැනක් ගැනයි. Gmail Inbox එකේ TAB වල ඇති සියලුම Email එකවර Select කිරීමේ ක්‍රමයක් බොහෝදෙනෙක් දැක නැතත් Inbox එකේම උඩින්ම තිබෙනවා. මේ සඳහා ඔබ කළයුත්තේ ඔබේ ඉන්බොක්ස් එකෙහි සාමාන්‍ය පරිදි පළමු පිටුවේ ඇති Emails සියල්ල සිලෙක්ට් කිරීම පමණයි. ඒ සඳහා ඔබට Select All විකල්පය තෝරාදිය හැකියි.

ඉන්පසු ඔබේ Inbox එකට අදාල Social කියන TAB  එකේ පළමු පිටුවේ ඇති ඊමේල් සියල්ල select කල හැක. එමෙන්ම එම Email සංඛ්‍යාව select වී ඇති බවත්, Social කියන TAB  එකේ ඇති සියලුම Email select කළහැකි විකල්පයකුත් එම Emails වලට ඉහළින් පෙනෙනු ඇති. 
පහත රූපයේ පරිදි රතු ඊතලයෙන් Social කියන TAB  එකේ අැති එදා මෙදා තුර පැමිණි  සියලුම Emails දිස්වේ.

දැන් ඔබ කළයුත්තේ මෙම Select all 489  conversations in Social යන්න මත ක්ලික් කිරීමයි. එවිට ඔබේ Social කියන TAB  එක තුළ එදා මෙදා තුර පැමිණි සියලුම Emails select වනු ඇත. දැන් ඔබට Delete මත ක්ලික් කර එම ඊමේල් සියල්ල එකවර මකා දැමිය හැකියි හැකියි.

ඉන්පසු ඔබේ Social කියන TAB එක clear වනු ඇති.

මේ අපි බොහෝදෙනෙකුගේ ඇස්වලට පෙනි පෙනී අපි නොදකින තවත් එක් දෙයක් විතරයි. තවත් මෙවැනි දේ ඇති. සොයා බලන්න.

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Main ways to Backup and Restore MariaDB

There are two types of backups called 

1. Logical backups

2. Physical backups

1. Logical backups

Logical backups consist of the SQL statements necessary to restore the data, such as CREATE DATABASE, CREATE TABLE andINSERT.

2. Physical backups

Physical backups are performed by copying the individual data files or directories.

Logical vs Physical backups

The main differences are as follows:

• logical backups are more flexible, as the data can be restored on other hardware configurations, MariaDB versions or even on another DBMS, while physical backups cannot be imported on significantly different hardware, a different DBMS, or potentially even a different MariaDB version.
• logical backups can be performed at the level of database and table, while physical databases are the level of directories and files. In the MyISAM storage engine, each table has an equivalent set of files, while in the InnoDBstorage engine, by default, a number of tables are stored in the same file, in which case it is not possible to backup by table.
• logical backups are larger in size than the equivalent physical backup.
• logical backups takes more time to both backup and restore than the equivalent physical backup.
• log files and configuration files are not part of a logical backup

Backup tools

mysqldump

mysqldump performs a logical backup. It is the most flexible way to perform a backup and restore, and a good choice when the data size is relatively small.

For large datasets, the backup file can be large, and the restore time lengthy.

mysqldump dumps the data into SQL format (it can also dump into other formats, such as CSV or XML) which can then easily be imported into another database. The data can be imported into other versions of MariaDB, MySQL, or even another DBMS entirely, assuming there are no version or DBMS-specific statements in the dump.

Examples

A common use of mysqldump is for making a backup of an entire database:

shell> mysqldump db_name > backup-file.sql

You can load the dump file back into the server like this:

shell> mysql db_name < backup-file.sql

Or like this:

shell> mysql -e "source /path-to-backup/backup-file.sql" db_name

mysqldump is also very useful for populating databases by copying data from one MariaDB server to another:

shell> mysqldump --opt db_name | mysql --host=remote_host -C db_name

It is possible to dump several databases with one command:

shell> mysqldump --databases db_name1 [db_name2 ...] > my_databases.sql

To dump all databases, use the --all-databases option:

shell> mysqldump --all-databases > all_databases.sql

For InnoDB tables, mysqldump provides a way of making an online backup:

shell> mysqldump --all-databases --single-transaction all_databases.sql

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