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Hard Disk Drives
In a personal computer, a hard disk drive controls the positioning, reading, and writing of the hard disk, where data is stored.
4,496 Questions
How do you partition a mac hard drive without losing data?
If you are running a recent version of Mac OS X you can use the Disk Utility software found in the Utilities folder within the Applications folder. As with all disc based operations it is good practice to have a back-up copy of your content. From the Disk Utility Help page (The Help menu is your friend):
Creating new partitions on a disk
You may be able to create multiple partitions on your disk without losing any data. Each partition works like a separate disk. You may need to create a new partition if you want to install multiple operating systems on your computer. Partitions can also help you organize your files.
NOTICE:Back up your data before creating new partitions on your disk as a precaution.
To create new partitions on a disk:
1. Select the disk from the list at the left, and click Partition.
2. Select an existing partition in the Volume Scheme list, and click Add (+). Disk Utility splits the partition into two, leaving the data in one of the new partitions. If the partition is less than half-full, Disk Utility creates two partitions of equal size. Otherwise, it creates one partition large enough for the data, and another partition with the remaining space.
3. Resize the partitions as needed. You can drag the dividers between the partitions in the Volume Scheme list, or you can select a partition in the Volume Scheme list, and then enter a value in the Size field.
4. Choose how to format the partitions that will be erased or created. For each new partition, select it, enter a name, and then choose a format.
5. Click Apply.
Or you can get under the bonnet and do all that geeky stuff:
You need to use the "diskutil" command line program, along with the "-resizeVolume" flag...
Here is the help information for this command:
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Disk Utility Tool
Usage: diskutil resizeVolume [Mount Point|Disk Identifier|Device Node] size
Non-destructively resize a disk. You may increase or decrease its size.
When decreasing size, you may optionally supply a list of new partitions to create.
Ownership of the affected disk is required.
Valid partition sizes are in the format of
Valid sizes are B(ytes), K(ilobytes), M(egabytes), G(igabytes), T(erabytes)
Example: 10G (10 gigabytes), 4.23T (4.23 terabytes), 5M (5 megabytes)
resizeVolume is only supported on GPT media with a Journaled HFS+ filesystem.
A size of "limits" will print the range of valid values for the current filesystem.
Example: diskutil resizeVolume disk1s3 10G JHFS+ HDX1 5G MS-DOS HDX2 5G
Valid filesystems: "Case-sensitive HFS+" "Journaled HFS+" "Case-sensitive Journaled HFS+" "HFS+" "HFS" "MS-DOS FAT32" "MS-DOS FAT16" "MS-DOS" "MS-DOS FAT12" "UFS" "Linux" "Swap"
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So here's what you need to do: (if you want to install a Linux partition)
In the example from the help command, they are creating a second and third partition on the disk - you don't need to do this (because diskutil doesn't create ext3 or ext4 partitions)...leave the space as "free" or unpartitioned space.
When I'm giving you commands below, a normal shell prompt is shown as a "$" (you don't need to type in the $)....
1.) MAKE SURE YOU AREN'T RUNNING ANY OTHER PROGRAMS WHEN YOU'RE RUNNING THESE COMMANDS. YOU WILL NEED TO RESTART THE MACHINE IMMEDIATELY AFTER THE PARTITION GETS RESIZED.
2.) Use the diskutil command line program to determine which device number your startup disk is:
$ diskutil list
This will list out information that shows device numbers (ie. disk0, disk1s5, etc.). Determine the identifier for your hard drive (it will be listed under "name" - you probably only have one partition, and it's probably the last on on the list).
/dev/disk0
#: type name size identifier
0: Apple_partition_scheme *149.1 GB disk0
1: Apple_partition_map 31.5 KB disk0s1
2: Apple_HFS Macintosh HD 148.9 GB disk0s3
3.) You need to determine how much free space you have available, and how much you want to split off for Linux (you will want to leave a little for the Mac side, but have enough for Linux or whatever you are doing)...For the most part, if you "Get Info" on the hard drive, and it shows that you have 95 GB capacity, and that 40 GB are used, 75 GB would be a good size to resize the Mac partition to (giving you 35 GB of space there, and 20GB free space for LInux)...
4.) To do the actual resizing, you'll need to use the "sudo" command to run the command as root:
$ sudo diskutil resizeVolume disk0s3 75GB
Describe how data are stored in a computer?
All RAM chips are laid out in a spreadsheet format. You have columns and rows. They are 8 bits across and could be millions of rows long depending on how much memory you have. The CPU tells the memory controller chips what column and row it wants for data and the MMC can find it in RAM.
What does formatting a floppy or hard drive do?
The headers on your file allocation table files are replaced with a special character. This character tells the operating system not toread any files still on the disk. At this point, files can still be recovered. Only if the files are written over will the files be altered and rendered unreadable. If an algorithm is used to write over the files, it may be necessary to write more than once. Otherwise, a decryption algorithm can be used and the files reconstructed.
Is the secondary storage faster than main memory?
No. The secondary storage is typically slowerthan primary storage. But the secondary storage has higher capacity than primary storage.
What are the three advantages of using SCSI over IDE?
compared to IDE and other buses, SCSI has the capability to 'disconnect' devices while they are working, thus freeing the bus for other devices.
So you can have up to 8 devices on a SCSI bus (OK, one typically is the controller); each time your system needs some data from a device, the controller sends the command to the device, then disconnects.
When the device has collected the data, it alerts back the controller, requesting the bus, and sending back the retrieved data.
In the meanwhile (after the command is sent, and before the answer is returned) the controller can handle other requests and answers from and to other devices on the same bus.
So SCSI is much more efficient than IDE, but only if you connect more than one device, and the more devices connect the more it is efficient (provided that you distribute your data in order to request accesses to more than one device, obviously!)
On the other hand, SCSI is more complex, so it is more expensive.
When arriving at a navigation lock what is order of priority?
Military Craft, Commerical Craft , Fishing Craft, then PWC
A terabyte is 1 trillion bytes (1,000,000,000,000 bytes)
Decimal system: 1000 Megabytes (MB) = 1 Gigabyte (GB)
1000 Gigabyte (GB) = 1 Terabyte (TB)
Binary system: 1024 GB = 1 TB
A terabyte or TB, is equal to 1,099,511,627,776 bytes. However, the International Electrotechnical Commission (IEC) defines a TB equal to 1012, or 1,000,000,000,000 bytes.
How is information stored magnetically to the computer hard drives?
Widely used Magnetic platters Hard disk drives uses Properties of Magnetism. As known Data is stored in Binary form, the disk uses North/South Polarity created on Magnetic disk platter as 0 or 1 (binary digits). The sensor (Read/Write Head) in Hard disk senses magnetic orientation at a very small area and interprets it as Binary Digit.
For storing data on Hard disk the magnetic orientations are changed according to data by Read/Write Head.
Cylinder
What is the function of a hard drive?
A hard disk is a device that is used to store large amounts of data in a computer system. Hard disks differ from other memory because they are non-volatile, they retain the data even when they do not have power.
Which two sizes does a Hard Disk Drive come in?
You can get almost any size in gigabytes you want in a hard drive. 50, 100, 500, whatever you feel they make it. In fact there are now hard drives that are larger than gigabytes, they are called TeraByes. A gigabyte is 1 billion characters.
Why would a toilet back up into the shower?
A down line clog would cause this. The shower drain is lower than any other drain in the bathroom so it is the first to tell you of a clog in the line. Time to Roto Rooter! Y-THINK-Y The toilet and shower must have the same drain. There is a blockage somewhere after the toilet and shower drains meet. The backup takes the easiest route back which must be the shower drain. Try snaking out both drains. Start with the toilet. To do the best job, remove the toilet and start from floor level.
What are the components of hard disk?
Most of the enclosure is made out of a metallic alloy however the main part of a hard drive, which stores the data magnetically, is called the platter. In a hard drive there are normally several platters. Platters can store data on both sides requiring a head (reader) for each side.
The core of the platters are typically made using an aluminum or glass and ceramic substrate shaped into a disk. Then the disk is coated with a thin layer of a mostly nonmagnetic metallic alloy and on top of this is a protective carbon-based overcoat. Both of these layers are applied in the same process which is called sputtering. The next layer of the disk is a nanometer thin polymeric lubricant applied by dipping the disk into a solvent solution. The surface of the disk needs to be flawlessly smooth so that the disk head can rapidly move over the surface.
Scott
Where can one find the cheapest hard drives?
This is not an easy question to answer.
If I put down the brand name and model number of a hard drive that I know is the cheapest per Gigabyte on the market, by the time I hit the save button the information is extremely likely be outdated and will definitely be outdated after 24 hours.
Due to competition, and availability of stock the price per GB of various brands and models of drives go up and down every time a new model is released, the last of a shipment is sold or a new deal is reached between a supplier and a customer.
During 2011 Hard drive prices went up due to natural disasters such as the floods in Thailand sutting down most of the factories that produce about 45 percent of the world's hard drives.
As of the start of June 2012 the best deal on hard drives per GB seams to be on some of the 2 and 3 Terabyte models. As more 4 Terabyte drives come on the market their per GB price will slowly improve till their cost per GB will most likely be similar or cheaper than the 2 and 3 Terabyte models.
But with Solid State Drive technology rapidly improving the hard drive might soon become a relic of the past.
It allows you to 'install' it without physically connecting it to ta computer (and possibly damaging the device or the computer in the process).
How many partitions does SCSI support?
SCSI does not care about partitions. This is only the protocol used to interface with the harddisk.
There is probably a practical limit to the possible number of partitions on your SCSI drive. This is limited by its size mostly.
Normal limitations on partitions is something like 3 Primary partitions and one extended of which can contain more logical partitions. However not being 100% sure about limitations I find it logical to be about 127 or 255.
In any case more than what is practical for most uses.
It is greatly dependent upon which operatingsystem you use.
A partition is only controlled via software or even software in hardware.
Designing software for it, and you can easily have thousands of "partitions".
it is like having a book. If you write the book yourselves, you decide how many chapters this book will consist of. You decide the size of each chapter.
How many primary partitions can you create on a single fixed disk drive using FDISK?
i have a new hard disk so what i should do ?
How many pictures can 500 GB hard drive store?
This can't be a precise answer because 12 MP photographs in JPG format vary in size quite a bit depending on how complex the photo is. A typical size is around 4 MB. (RAW files are much larger, closer to 20 MB). Your 500 GB drive will usually have about 450 GB of usable space. That gives you about 100,000 photos in JPG format. That number drops quite a bit if you have Photoshop files of each picture or have RAW files.
How do you access your external hard drive and the files on it with command prompt?
In the same way how you access local disks, you just need to know an external drive name.
How do you erase files from an external hard drive?
You can use the DOS utility which is called format. In order to be able to erase a hard drive you have to boot your computer in DOS or Linux and then to use format utility. Format does not erase files. You can still find files with recovery program. If you want to avoid this over write hard disk with a program like ErAce
How do you delete files from hard drive?
The simple way is to drag and drop a file into 'Recycling Bin' on your desktop, and then empty it by right-clicking, and selecting 'Delete'. You can also right-click on the file, choose 'Delete'. IT exports suggest using free tools like 'Eraser' to securely clean material from a hard drive so it is permanently gone.
How many primary partitions can be created?
On Intel x86 PCs, there are two main parts of memory that are further divided into smaller sub-parts:
Low memory (0 to 1MB). This memory is all you can get if you are in real mode (such as when you are running DOS without Extended Memory.). Your modern OS usually will only need this if it really needs to talk directly to the BIOS, such as to set things up and output graphics. Here you have:
- Free memory that the OS can use (to boot up)
- BIOS data
- Video memory
- Memory-mapped BIOS ROM
- The Interrupt Vector Table (used only by DOS and boot programs)
High memory (1MB to whatever you have installed). This part of memory is the most spacious and is what your operating systems and programs normally use.
- LOTS of free memory
- Memory reserved for memory-mapped devices
- Some more BIOS data and code
There is more information out there on the Web, check the related links for some.
