what is the difference between the usb booting mechanism and optical disk booting mechanism?
Many distributions of linux/bsd have separate usb and dvd images and writing the dvd image doesn’t seem to work. What is fundamentally different between these two mechanisms?
4 Answers 4
First of all, USB means Universal Serial Bus. It is a standard for a control and data bus, just like PCIe, PCI, EISA and ISA are all buses. USB is not a device, like a CD or DVD drive. (Optical drives typically use SATA or IDE buses with the ATA protocol.) When you use or refer to USB, there is probably an attached device (aka USB gadget) that you are actually referring to.
In this case you are probably referring to USB flash drives, which essentially emulate a typical hard disk drive. If the PC’s BIOS supports booting from a USB device, then that means that the BIOS has embedded firmware that includes a USB protocol stack, and can control a target device like a flash drive over the Universal Serial Bus. After the USB handshake protocol is established between the USB host (the PC that needs to boot) and the USB gadget (the flash drive), the control and data mechanism provided by USB can be abstracted away, and upper layers of the BIOS boot code can treat the flash drive just like a HDD. That is, the first sector of the "disk drive" has to be read in order to obtain its Master Boot Record (MBR).
Optical discs do not conform to the PC hard disk layout (there is no MBR at sector zero). In fact there are several formats for optical disks, but the data layout in common use with PCs is the ISO 9660 format for CDs. The requirements for booting from CD/DVD are spelled out in the ISO 9660 standard.
The data transfer rate and physical capacity difference between different boot devices essentially become irrelevant if the BIOS supports the device. The I/O characteristics of each supported boot device has to be accounted for, and are handled in the low-level device driver code of the BIOS. Note that most PCs can also boot from the Ethernet network interface card (NIC), and that interface is far more different than CD/DVD versus HDD. Yet the layered approach to software implementation delegates all that low-level I/O and protocol handling to lower layers, and the BIOS can proceed to load & execute the next stage of boot loader. Note that some device differences are parameterized. That is, the device’s number of cylinders, heads, sectors/track and sector size are not hard coded in the device drivers, but rather are read from the device, e.g. the BPB in the MBR.
. writing the dvd image (to the USB flash drive) doesn’t seem to work.
The difference between these two media layouts can be dissolved by combining the two into a merged image file that can be copied to either a CD/DVD or a HDD/flash drive. An ISO image (for burning to a CD or DVD to make a bootable disc) can be modified for straight copying to a HDD or USB flash drive to produce a Hybrid ISO/IMG image:
The Hybrid ISO/IMG format is a modification of the standard ISO format to make the image compatible with the expectations of hard drive booting
A standard ISO image typically includes the ISOLINUX boot loader which is loaded by the BIOS using the El Torito booting standard. The Hybrid image replaces the first 512 bytes of the ISO format (which is all binary zeros) with a PC hard drive Master Boot Record (MBR) containing: The stage 1 loader image from GRUB version 0.97, and a partition table with 1 partition that ends at the end of the hybrid image. The remainder of the ISO image is not modified.
Additional sectors are added at the end of the ISO image.
What Is Optical Drive? How Does It Work?
A computer system with an optical drive allows users to use DVDs, Blu-ray discs, or CDs. However, the iCloud market and other better data management devices have supplemented this visual drive method. As a result, optical drives have become less common than before.
While many people still prefer touchable and visible storage devices to digital ones, they must know how an optical drive works and when they would need an optical drive. That’s what we will introduce in this guide. Keep reading.
In this article
What Is An Optical Drive?
An optical drive is like a luminosity that can observe and read the data provided by the optical disks. Optical drives have almost replaced magnetic drives since the laser technology of optical disc drives makes it more convenient than magnetic drives’ magnetic storage media for data storing.
The optical drive is associated with multiple optical discs such as Blu-ray, CDs, or DVDs, and it is commonly used for installing various software from discs.
Optical drives work by rotating the disc at a constant speed, measured in RPM (rotation per minute). The drive uses advanced high-tech laser beams to read and observe the data, and its interface is smaller than computers.
There are various types of optical discs. From which, we can divide them into readable, erasable, or writable discs. The discs include CD-ROM, CD-R, CD-RW, DVD-ROM, and Blu-ray discs.
CD, DVD And Blu-ray Disk
Features
Blu-Ray
CD
CD stands for compact discs, a digital data storage device that is read by the optical drive with the help of laser beam technology. It can be easily handled and does not require special knowledge to operate a compact disc. 650.55 or 700.09 MB of data can be stored on a conventional 120 mm CD-ROM.
Features of CDs
- made up of plastic and reflective material.
- available to store audio, video, and text files.
- portable and easy to use without any special software.
DVD
DVDs are called Digital Versatile Discs, which are optimum for storing digital data. A type of optical disc similar to a CD’s size will have much more storage capacity. The difference between DVDs and CDs is that DVDs have dual sides, whereas CDs have only one side. Based on storage capacity, DVDs can store anywhere from 4.69 GB to 16.99 GB.
Features of DVDs
- more magnificent in terms of storage.
- it is widely used to store computer files or video programs.
- specific in terms of the type of disc.
Blu-ray disc
The Blu-ray disc is a highly formatted storage disc that can store approximately four times more data than a CD or DVD. Blu-ray discs can store data up to 100.058 GB. Actual Discs read speeds of 4.501 MBps before. But, the present scan speed of these discs is approximately 8.99 MBps to 35.99 Mbps.
Blu-ray Disc Advantages
- the data stored on Blu-ray Disc is rewritable and recordable.
- it enables us to produce high-quality playback videos.
DVD-R And DVD+R
DVD-R
The term DVD-R means Digital Versatile Disk Recordable and is pronounced as DVD «dash R» or «minus R.» It is a disc designed to write the data once, but it allows us to read that data multiple times. The format of this disc has been officially approved. Its design is almost the same as the regular DVD drive. It functions at the location of the laser beam by using the tiny particles on the disc.
- cheap
- it uses LPP criteria for speed control.
- land permits to process data.
DVD+R
DVD+R refers to Digital Versatile Disk Recordable as well. It is marked as DVD «plus R.» It is the updated version of the DVD-R disc, allowing users to format the written and recorded information. However, this version is not officially approved by the DVD and does not contain any logo from the DVD.
- efficient results
- the ADIP system determines the working of the laser.
- simultaneous formatting
Recordable Disc And Rewritable Disc
Recordable Discs
Rewritable Discs
Recordable Disc
A recordable disc is a disc on which you have no flexibility to change the data, which works as a one-time recordable disc. It has a dye-based layer that assists in recording media files, like audio, video, photographs, and data files. If you do not need to rewrite or format the recorded data, this kind of disc can be your favorite. And these discs have an 8X writing speed with a 24% reading speed.
Features of a Recordable Disc
- quick and effective
- It is less costly
Rewritable Disc
In contrast, a rewritable disc provides so much more flexibility to you than the recordable ones. It allows you to rewrite the data or re-record data onto your disc. You can use this disc multiple times and for the long term. Though it is a little expensive, it is worthy because of its reusability. Rewritable discs use a laser of a higher power than recordable ones. And they have a 4X writing speed with 32X reading speed.
Features of the Rewritable Disc
- multiple rewrites
- it uses its particular RW drives.
- economical
Features of An Optical Drive
Since the advent of DVD drives, you might soon discover another version of the drive will be in front of us. Nowadays, however, many PCs and laptops come with optical drives, and only a few people still use floppy discs. It might be rather difficult even to find a computer these days that can read a floppy disk. So, here are some features provided by us. We are sure that these features will help you decide whether to use optical drives or not.
- Optical disc drives read waves near the light spectrum using a laser or an electromagnetic head.
- This uses light to read and access the information provided by the user. In addition, this drive helps store macro details in a small space.
- It is faster than traditional magnetic drives.
- It gives you the ability to read and write at a more rapid pace.
- Optical drives can save your space as well as time.
Internal Optical Drive (IOD) And External Optical Drive (EOD)
An external optical drive is an optical drive that is placed outside the chassis. Whereas an internal optical drive is a built-in optical drive that is stable in the device.
External optical drives include USB 2.0, USB 3.0, and USB C, but on the other hand, internal visual purposes include Panasonic, Samsung, Lite-on, or other drives. Both industries are different because the visible internal movement is immovable. In contrast, the external optical is portable and mobile.
Features
Internal Optical Drives
External Optical Drives
Optical Drive Media Formats
Various optical drive media formats are used for different operating systems. These media formats are like a system architecture that manages the files and volume of information or passes the directory to the system. So for example, an optical drive can store video files, games, multimedia files, directories, and so on. And the optical drive media formats are to record and observe data.
The commonly used optical drive media formats are DVD, DVD-R, DVD+R, DVD+RW, CD-RW, CD-ROM, CD-R, and DVD-RAM.
Video Tutorial on Optical Disk Explained
How to Recover Data from a Damaged Optical Drive?
It happens that the optical disk gets scratched or lost, which can cause the disk unreadable, and then all the data will get lost. Then is it possible to recover data from the damaged optical drive?
Wondershare Recoverit is a data recovery software that empowers you to restore data from various places. Any form of data is recoverable, like word documents, image files, media files like audio and video, etc. All you need to do is install the app, select where you need to recover the data, then click Recover to let the app scan the disc and restore the files you are trying to get back.
Click here to get more information about recovering data from DVD drives.
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Insert one end of the USB cable into the external CD drive. Plug the other end of the cable into your computer’s USB port. Allow the computer to install the drivers for your external CD drive. Usually the computer will recognize the external drive and automatically install the drivers for the device.
Is USB an optical drive?
Flash drives, also known as USB drives or jump drives, contain mini circuit boards with memory chips to save and retain your data and information. This type of storage media is called solid state memory, and differs from optical and magnetic drives.
Do we need optical drive anymore?
Optical drives, that can read and write CDs, DVDs, and sometimes Blu-ray discs, have been an important part of the PC universe for a long time. But there’s less and less need for them. Most users download and stream music and movies these days rather than buy them on a shiny five-inch disc.
What is an external optical drive?
Optical drives let your computer read and interact with discs like CDs, DVDs, and Blu-rays. While nearly every computer had them a few years ago, they’re rare to see on new computers now. If you need an optical drive but your computer doesn’t have one, you can buy an external optical drive.
What can I do with an old optical drive?
What to Do With Your PC’s Unused Optical Drive Bays
- Fill It Up With Storage Drives.
- Add a Hot Swap Storage Bay.
- Expand Your USB Ports and Card Readers.
- Add a Fan Controller.
- Use It as a Watercooling Reservoir.
- Turn It Into a Literal Storage Drive.
- Add a Cup Holder.
Is a memory Stick magnetic storage?
There are three main types of secondary storage in a computer system: solid state storage devices, such as USB memory sticks. magnetic storage devices, such as hard disk drives.
What is the difference between an optical drive and a hard drive?
Optical drives are hardware devices that are used to read / write storage devices like CD / DVD ROMs. Hard-disk drives are physical devices that are used to store data on them. They can be magnetic drives (HDD) or solid State drives (SSD). They store information on themselves.
How do I connect my Samsung DVD player to my laptop?
Put the wanted DVD disc into the Samsung laptop DVD player and double-click on the Leawo icon to see the interface. The sweet software will detect the Samsung laptop DVD drive and catch the DVD source automatically.
How do I use a DVD writer?
How to Use a DVD Burner
- Open your DVD burning software.
- Select the DVD burner you wish to use when prompted.
- Select the type of files you wish to burn when prompted.
- Select the specific files you wish to burn when prompted.
- Enter in a name for your disc when prompted.
- Click burn.
Can a Samsung PC boot from a flash drive?
Boot your Samsung PC from a USB drive or optical media There are times when you may want to boot your computer from external storage, using an operating system or specialized software that is provided on a CD-ROM or USB flash drive. A common example is a memory diagnostic tool.
What makes Samsung Ultra Slim Black optical drive eco friendly?
The Buffer Under Run technology prevents errors that can be caused when writing speeds exceed data transfer speeds, while also enabling PC multi-tasking. SE-208GN is manufactured in an eco-friendly manner, with lead-free soldering technology that restricts the use of harmful materials such as Pub, cd, cr+6, Hg, PBBs and PBDE.
Can you play a DVD on a Samsung Slim?
Chrome OS doesn’t support playing or burning discs. It only supports reading data CDs and DVDs, such as software installation discs. This and pretty much any other external optical drive can be used for that. The Samsung slim models only require one powered USB 2.0 (or 3.0) port, no other power is needed.
What kind of operating system does Samsung PC support?
Samsung can only provide support for the Windows operating system that ships with your PC. Alternative operating systems, including other versions of Windows, may not support all the hardware or features of your device. For assistance with using and installing alternative operating systems, contact the publisher.
Is USB an optical drive?
Flash drives, also known as USB drives or jump drives, contain mini circuit boards with memory chips to save and retain your data and information. This type of storage media is called solid state memory, and differs from optical and magnetic drives.
Do PCS still have optical drives?
Optical drives have just about been phased out from modern laptops, allowing them to reach an ever thinner and lighter form factor. However, a PC user can still choose if they wish to give in to the storage and media revolutions of the decade.
What is an external optical disk drive?
An optical drive is an internal or external computer disk drive that uses laser beam technology to read and write data. Optical disk drives are associated with compact discs, DVD and Blue-Ray technology.
Is a Memory Stick magnetic storage?
There are three main types of secondary storage in a computer system: solid state storage devices, such as USB memory sticks. magnetic storage devices, such as hard disk drives.
Do I really need an optical drive?
Optical drives, that can read and write CDs, DVDs, and sometimes Blu-ray discs, have been an important part of the PC universe for a long time. But there’s less and less need for them. Most users download and stream music and movies these days rather than buy them on a shiny five-inch disc.
Can you play old PC games on an external DVD drive?
Yes, this external cd drive can play computer games. Just connect it to a computer and insert your game disc.
What is the best optical drive?
The Best External Optical Drive LG Electronics 8X USB 2.0 DVD External Optical Drive. This slim and compact DVD writer is the perfect companion for the modern individual who enjoys a good blast from Rioddas External Optical Drive. As far as external DVD writer go, this is a highly functional one. Verbatim Slimline Blu-ray External Optical Drive. ASUS Powerful Blu-ray Drive.