Interview Questions

Chmod() is used for changing permissions on a file.

Syntax:

Chmod(file, mode)

Mode here specifies the permissions as follows:

The first number is always zero

The second number specifies permissions for the owner

The third number specifies permissions for the owner's user group

The fourth number specifies permissions for everybody else

Possible values (to set multiple permissions, add up the following numbers)

1 = execute permissions

2 = write permissions

4 = read permissions

Example:

// everything for owner, read for owner's group

chmod("test.txt",0740);

TTL is a value in data packet of Internet Protocol. It communicates to the network router whether or not the packet should be in the network for too long or discarded. Usually, data packets might not be transmitted to their intended destination within a stipulated period of time. The TTL value is set by a system default value which is an 8-bit binary digit field in the header of the packet. The purpose of TTL is, it would specify certain time limit in seconds, for transmitting the packet header. When the time is exhausted, the packet would be discarded. Each router receives the subtracts count, when the packet is discarded, and when it becomes zero, the router detects the discarded packets and sends a message, Internet Control Message Protocol message back to the originating host.

A database is used to store, modify, extract and to search for the data within it.

- Fail-safe approach defines the level that divides the security such that it is safe even in case the system is failed.

- The fail safe approach doesn’t allow an attacker to take the advantage by breaking in the system and crashes out.

- This approach allows the web server to perform the routines even if the system runs out of the memory in case of any attack. 

- The system in attacks doesn’t skip the access to the control check or it doesn’t skip serving any document requested. 

- Fail safe approach can force the web server to run of the memory and have a DoS attack.

• Intelligent Search and Siri- Intelligent Search is an excellent mechanism to learn user habits and act on that information- open apps before we need them, make recommendations on places we might like and guide us through our daily lives to make sure we’re where we need to be at the right time.
  Siri is a personal assistant to the users, able to create contextual reminders and search through photos and videos in new ways. Swiping right from the home screen also brings up a new screen that houses “Siri Suggestions,” putting favorite contacts and apps right on your fingertips, along with nearby restaurant and location information and important news.


• Deeper search capabilities can show results like sports scores, videos, and content from third-party apps, and you can even do simple conversions and calculations using the search tools on your iPhone or iPad.


• Many of the built-in apps have been updated.
  ✓ Notes includes new checklists and sketching features
  ✓ Maps now offers transit directions
  ✓ Mail allows for file attachments
  ✓ Apple Pay is being improved with the addition of store credit cards and loyalty cards
  ✓ Leading “Passbook” to be renamed to “Wallet” in iOS 9.


• San Francisco font, wireless CarPlay support


• An optional iCloud Drive app, built-in two-factor authentication and optional longer passwords for better security.


• Performance improvements

Payroll Transaction is nothing but the calculation of salary for a month / week / day of an individual / group of employees depends upon the attendance / variable inputs / other benefits / salary component and generate the reports for IT / Statutory / PT payments.

unlink()-deletes the given file from the file system.
unset() -makes a variable undefined.

- A clustered index is a special type of index that reorders the way records in the table are physically stored. Therefore table can have only one clustered index.

- A non clustered index is a special type of index in which the logical order of the index does not match the physical stored order of the rows on disk. The leaf node of a non clustered index does not consist of the data pages. Instead, the leaf nodes contain index rows.