Logical data error

Cyclic Redundancy check well known as CRC is an error detection code that gives data error cyclic redundancy check if it identifies any changes to the data that is being stored, accessed, or transferred onto a storage device like CD/DVD, SD card, or a hard drive.

In further detail when CRC is set up on a device it forms a codeword for data that is to be stored or sent to another storage media. The code word consists of check values that are calculated block-wise before the storage of data.

While the data is being accessed by computer, the codeword or the check values are compared with current values of accessed data and any mismatch in the values results in data errors. This would mean inaccessible data due to hard drive or SD card corruption.

Read this article to understand how to fix data error cyclic redundancy check on various storage devices, beginning with understanding error, solutions are discussed that conclude with a method that involves the least risk of data loss while solving the CRC error.

Table of Contents:

1. What is Cyclic Redundancy Check Error?
2. What Causes CRC Error?
3. How to Solve Cyclic Redundancy Check Error?
4. How To Recover Data From Inaccessible Drive?

Event 1: Encountering CRC data error

As shown in the image above an error message shows up when you try to open a file or folder on an SD card, or hard drive. Usually, the data becomes inaccessible due to logical data error (corruption) or physical damage.

In the following sections we will broadly discuss the below errors and solutions to solve data error CRC:

• CRC error on internal and external hard drives
• Data error (cyclic redundancy check) on SSD
• Cyclic redundancy check data error on SD cards
• Cannot initialize disk: Cyclic Redundancy Check
• Cannot copy data cyclic redundancy check
• Data error cyclic redundancy check no drive letter

While it’s common for the CRC error to occur on external hard drives and portable media like SD cards or flash drives, it can also happen to internal drives and their partitions; in cases like these, you will find the drive to be unallocated or not initialized in Disk management.

Even though you try to initialize the disk from Disk management an error “Cannot initialize disk” comes up. The immediate course of action is to understand the causes in order to fix the data error cyclic redundancy check.

Event 2: Learning the causes of error Cyclic Redundancy Check:

As soon as you encounter a CRC error, it becomes very beneficial to learn what causes these errors. Some of the major causes of CRC errors include:

• Shutting down the computer while the hard drive is connected to it.
• Ejecting the external hard drive while the writing process is being carried out.
• Presence of bad sectors on the storage device.
• Severe virus or malware infection.
• Cluttered hard drive or registry errors.

The above-listed reasons cause logical errors except for bad sectors. Bad sectors on the hard drive are formed due to physical damage or wear and tear during read/write operations on the storage device like SSD or flash drive.

Did you know?

Bad sectors on a storage device can further harm your drive and Windows data existing on the drive. You can create a disk image that has the contents and structure of all the data existing on the hard disk. Stick to the end of the article to know the safest way to recover data by creating a disk image.

«Remo recover creates a disk image by skipping all the bad sectors that are causing data error. This disk image is saved on a different hard drive or storage location which can then be used to recover data without any corruption or CRC errors.»

Event 3: Use free ways to repair data error Cyclic Redundancy check

There are various methods to fix the Cyclic Redundancy Error on External HDD. Here are a couple of handy techniques for resolving CRC errors:

Method 1: Fix data error (Cyclic Redundancy Check) using CHKDSK Utility

The computer has a built-in program to find and fix system errors. Even, this tool helps in eliminating bad sectors from further usage. Let’s see how to use Disk Utility to solve the CRC error-

1. Connect external hard drive OR to computer and select it using mouse
2. Right-click on it and select Properties from the context menu
3. In the properties window, select the “Tools” tab
4. Then, under error checking, click on the “Check Now” button
5. From the next window, select both “Automatically fix file system errors” and “Scan for and attempt recovery of bad sectors” and click on the “Start” button
6. Wait until you get a dialogue box as seen below:-

Method 2: Removing CRC errors using CHKDSK Command

1. Run command prompt as administrator by typing in CMD in the search box on the taskbar and right-click on the command prompt suggestion to select the Run as administrator option.
2. Find the Windows drive letter by opening This PC or File explorer and look for an external drive or partition that has a Cyclic Redundancy Check error to note the drive letter.
3. In the command prompt window type “chkdsk drive letter: /f” ex: if the drive letter of the storage device or partition that has CRC error is “k” then the command is “chkdsk k: /f”

The suffix “/f” is used to fix drive errors. The scan takes a while and fixes any logical errors as shown below

Method 3: How to solve Cyclic Redundancy Check error using SFC scan:

SFC or system file checker is a tool that scans all protected system files of the operating system including registry files and replaces them with a copy from a cached folder. However, this method can cause data loss if the data error is caused due to bad sectors or a virus

Using the steps below SFC scan can solve CRC errors due to registry corruptions as well:

1. Open command prompt by running it as an administrator.
2. Type the command sfc /scannow and the file checking process begins as shown below
   
3. After a brief amount of time if you see the message “Windows Resource Protection found corrupt files and successfully repaired them”, restart your computer and reopen the drive without any error.
4. If you see the error message “Windows Resource Protection found corrupt files but was unable to fix some of them”, you would need a more safer and trusted approach like using a data recovery software capable of creating a disk image.

Event 4: Recover data from the inaccessible drive using data recovery software

Data recovery software, especially Remo Recover can be an excellent workaround to data errors indicated by Cyclic Redundancy Check. When corrupted data is accessed multiple times, there are greater chances of data loss.

Additionally when the memory card, HDD or SSD has bad sectors, continuously trying to read from the sectors can completely eliminate the chances of data recovery as it further damages the sector.

Hence a successful attempt to solve the CRC errors using any of the free methods would still mean that you might not get your hands on your precious data.

Remo Recover is built with a deep scan engine that can rigorously look for lost files beyond file systems to recover data from each sector of the hard drive.
Download and try the tool for free now!!!

The safest way to fix data error (Cyclic Redundancy Check):

1. Download and install Remo Recover on the computer
2. Connect the external drive or memory card which has data error to the computer.
3. Launch Remo Recover, select the drive from the main screen, and hit the Scan button.
   Note: If you are unable to detect the external hard-drive click on the Can’t Find Drive option.
   
4. The tool will initiate a Quick Scan, Once the Quick scan is completed the tool will automatically start the Deep Scan which scans your drive thoroughly to recover your data. Click on Dynamic Recovery View to view the recovered files as and when the scan progresses.
   
5. You can make use of Advanced Filter and sort the recovered files according to your preferences.
   
6. Preview the recovered files by tapping twice on the files that you want to view.
   
7. Browse for a different folder/drive and click on the OK button to start the data saving process. 

This is difficult.

I think we should;

1. Return 4xx errors only when the client has the power to make a change to the request, headers or body, that will result in the request succeeding with the same intent.

2. Return error range codes when the expected mutation has not occured, i.e. a DELETE didn’t happen or a PUT didn’t change anything. However, a POST is more interesting because the spec says it should be used to either create resources at a new location, or just process a payload.

Using the example in Vish’s answer, if the request intends to add employee Priya to a department Marketing but Priya wasn’t found or her account is archived, then this is an application error.

The request worked fine, it got to your application rules, the client did everything properly, the ETags matched etc. etc.

Because we’re using HTTP we must respond based on the effect of the request on the state of the resource. And that depends on your API design.

Perhaps you designed this.

PUT { updated members list } /marketing/members

Returning a success code would indicate that the «replacement» of the resource worked; a GET on the resource would reflect your changes, but it wouldn’t.

So now you have to choose a suitable negative HTTP code, and that’s the tricky part, since the codes are strongly intended for the HTTP protocol, not your application.

When I read the official HTTP codes, these two look suitable.

The 409 (Conflict) status code indicates that the request could not be completed due to a conflict with the current state of the target resource. This code is used in situations where the user might be able to resolve the conflict and resubmit the request. The server SHOULD generate a payload that includes enough information for a user to recognize the source of the conflict.

And

The 500 (Internal Server Error) status code indicates that the server encountered an unexpected condition that prevented it from fulfilling the request.

Though we’ve traditionally considered the 500 to be like an unhandled exception :-/

I don’t think its unreasonable to invent your own status code so long as its consistently applied and designed.

This design is easier to deal with.

PUT { membership add command } /accounts/groups/memberships/instructions/1739119

Then you could design your API to always succeed in creating the instruction, it returns 201 Created and a Location header and any problems with the instruction are held within that new resource.

A POST is more like that last PUT to a new location. A POST allows for any kind of server processing of a message, which opens up designs that say something like «The action successfully failed.»

Probably you already wrote an API that does this, a website. You POST the payment form and it was successfully rejected because the credit card number was wrong.

With a POST, whether you return 200 or 201 along with your rejection message depends on whether a new resource was created and is available to GET at another location, or not.

With that all said, I’d be inclined to design APIs that need fewer PUTs, perhaps just updating data fields, and actions and stuff that invokes rules and processing or just have a higher chance of expected failures, can be designed to POST an instruction form.

Error is an illegal operation performed by the user which results in the abnormal working of the program. Programming errors often remain undetected until the program is compiled or executed. Some of the errors inhibit the program from getting compiled or executed. Thus errors should be removed before compiling and executing. 

The most common errors can be broadly classified as follows:

1. Run Time Error: 

Run Time errors occur or we can say, are detected during the execution of the program. Sometimes these are discovered when the user enters an invalid data or data which is not relevant. Runtime errors occur when a program does not contain any syntax errors but asks the computer to do something that the computer is unable to reliably do. During compilation, the compiler has no technique to detect these kinds of errors. It is the JVM (Java Virtual Machine) that detects it while the program is running. To handle the error during the run time we can put our error code inside the try block and catch the error inside the catch block. 

For example: if the user inputs a data of string format when the computer is expecting an integer, there will be a runtime error. Example 1: Runtime Error caused by dividing by zero 

Runtime Error in java code:

Exception in thread "main" java.lang.ArithmeticException: / by zero
    at DivByZero.main(File.java:14)

Example 2: Runtime Error caused by Assigning/Retrieving Value from an array using an index which is greater than the size of the array 

RunTime Error in java code:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 9
    at RTErrorDemo.main(File.java:10)

2. Compile Time Error: 

Compile Time Errors are those errors which prevent the code from running because of an incorrect syntax such as a missing semicolon at the end of a statement or a missing bracket, class not found, etc. These errors are detected by the java compiler and an error message is displayed on the screen while compiling. Compile Time Errors are sometimes also referred to as Syntax errors. These kind of errors are easy to spot and rectify because the java compiler finds them for you. The compiler will tell you which piece of code in the program got in trouble and its best guess as to what you did wrong. Usually, the compiler indicates the exact line where the error is, or sometimes the line just before it, however, if the problem is with incorrectly nested braces, the actual error may be at the beginning of the block. In effect, syntax errors represent grammatical errors in the use of the programming language. 

Example 1: Misspelled variable name or method names 

Compilation Error in java code:

prog.java:14: error: cannot find symbol
            + sum);
              ^
  symbol:   variable sum
  location: class MisspelledVar
1 error

Example 2: Missing semicolons 

Compilation Error in java code:

prog.java:8: error: ';' expected
        System.out.println("Welcome to " + s)
                                             ^
1 error

Example: Missing parenthesis, square brackets, or curly braces 

Compilation Error in java code:

prog.java:10: error: ')' expected
        for (i = 1; i <= 5; i++ {
                               ^
1 error

Example: Incorrect format of selection statements or loops 

Compilation Error in java code:

prog.java:12: error: not a statement
        for (i = 1, i <= 10; i++) {
                      ^
prog.java:12: error: ';' expected
        for (i = 1, i <= 10; i++) {
                                ^
2 errors

Logical Error: A logic error is when your program compiles and executes, but does the wrong thing or returns an incorrect result or no output when it should be returning an output. These errors are detected neither by the compiler nor by JVM. The Java system has no idea what your program is supposed to do, so it provides no additional information to help you find the error. Logical errors are also called Semantic Errors. These errors are caused due to an incorrect idea or concept used by a programmer while coding. Syntax errors are grammatical errors whereas, logical errors are errors arising out of an incorrect meaning. For example, if a programmer accidentally adds two variables when he or she meant to divide them, the program will give no error and will execute successfully but with an incorrect result. 

Example: Accidentally using an incorrect operator on the variables to perform an operation (Using ‘/’ operator to get the modulus instead using ‘%’) 

Reversed number is 7870

Example: Displaying the wrong message 

Finding the largest number 

8 is the smallest Number

Syntax Error:

Syntax and Logical errors are faced by Programmers.

Spelling or grammatical mistakes are syntax errors, for example, using an uninitialized variable, using an undefined variable, etc., missing a semicolon, etc.

int x, y;
x = 10 // missing semicolon (;)
z = x + y; // z is undefined, y in uninitialized.

Syntax errors can be removed with the help of the compiler.