Write once read many facts for kids
Write Once Read Many (WORM) is a special way to save information on a data storage device. Once you save something on a WORM device, you cannot change it or delete it. It's like writing with a permanent marker!
This means your information stays safe and exactly as you saved it. It helps prevent mistakes from people, computer problems, or harmful software. WORM makes sure important files are kept safe and cannot be accidentally changed or deleted. This helps keep your saved information real and secure.
History of WORM Storage
Long ago, even before CD-Rs and DVD-Rs, there were WORM drives. One example was the IBM 3363. These drives often used large, special disks that could only be written on once. Libraries used them to store lots of information that needed to stay the same.
Older ways to store data, like Punched cards and paper tape, were also WORM media. Once you punched a hole, you couldn't un-punch it! Also, Read-only memory (ROM) is a type of WORM storage. It's memory that computers use for basic instructions, and you can't change what's on it.
Modern WORM Devices
Today, common WORM devices are CD-Rs, DVD-Rs, and BD-Rs. These are the discs you use with your computer. Once you save something on them, you can't record over that same spot again.
You might think you can add more files or even new versions of a file to these discs. This is because of a trick called "packet writing." It makes the disc seem like it can be changed. But what actually happens is that new information is saved in a different, empty part of the disc. The old information is still there, but the computer just looks at the newest version.
SD cards and microSD cards also have a way to protect data. Some full-size SD cards have a small switch on the side. When you flip this switch, it tells the card reader not to write new information. However, the card reader needs to be built to listen to this switch for it to work.
Big companies also use WORM storage. They use special magnetic storage systems to keep their important data safe from being changed. These systems make sure that once data is saved, it cannot be altered. This is very important for keeping records that must stay exactly the same.
Research into New WORM Tech
Scientists are also looking into new types of WORM storage made from special materials like plastics. These new WORM devices could be used in small, low-power devices like RFID tags. This would help these tags store information that needs to be permanent and secure.
See also
In Spanish: Write Once Read Many para niños
