HD Doctor Blog

TPI (Tracks per inch)
The number of tracks written within each inch of the disk’s surfaces, used to measure how closely the tracks are packed on a disk surface. Also known as track density.

Tagged Queuing
The ability of the drive to receive multiple I/O processes from each initiator.

Task File
The set of I/O Host Interface Registers used to transfer status, commands, and data between the host and the drive for the EIDE interface.

Thin Client Architecture
A computer system in which data is stored centrally, with only limited storage capacity at the various points of use.

Thin Film
A type of coating deposited on a flat surface through a photolithographic process. Thin film…

SCA-2
SCA-2 (Single Connector Attach) interface incorporates a grounding contact, blindmate connector, direct plug misalignment tolerance, ESD protection, hot swap capability, and backplane connector options for SCSI devices. SCA-2 is commonly called the 80-pin SCSI connector.

SCSI Configure Automatically (SCAM)
Allows users to attach SCSI devices without worrying about configuration options.

SCSI-1
The Small Computer System Interface (ANSI document X3.131-1986).

SCSI-2
The Small Computer System Interface (ANSI document X3.131-1994).

SCSI-3
The ANSI X3T10 Working Documents (under development).

SCSI device
A host computer adapter, a peripheral controller, or an intelligent peripheral that can be attached to a SCSI bus.

SPC
SCSI Primary Commands.

Small Computer System Interface (SCSI)
An interface between a computer…

RLL (Run Length Limited)
An encoding scheme used during write operations to facilitate data readback.

ROM (Read Only Memory)
Integrated circuit memory chip containing programs and data that the computer or host can read but cannot modify. The computer can read instructions out of ROM, but cannot store data in ROM.

RPM (Revolutions per Minute)
Rotational speed of the media (disk), also known as the spindle speed. Hard drives typically spin at one constant speed. The slower the RPM, the higher the mechanical latencies. Disk RPM is a critical component of hard drive performance because it directly impacts the rotational latency.

Radial Path
The straight-line path from the center of the disk to the outer edge…

When a laptop hard drive becomes "unbootable", and you are unable to repair it, you can often save the data on the hard drive by using a "slave drive" recovery method on a desktop computer. As long as the laptop hard drive has not been mechanically broken and the disk is still "readable", you should be successful in accessing and preserving the valuable data on the drive.

I know the frustration when you delete something you shouldn’t have, or your hard drive is corrupted. I will show you how to do a data recovery and hard drive recovery from a desktop computer or on a laptop computer. There is some software you can use to undelete software, or even…

PC
Personal computer.

PRML (Partial Response Maximum Likelihood)
A read channel using sampled data, active equalization and Veterbi detection to accurately retrieve the user data off the disk.

Partition
A way to logically divide a hard drive so that an operating system treats each partition as a separate hard drive. Each partition has a unique drive letter.

Passive Termination
A termination architecture that is used to match the impedance at the end of the SCSI bus by using a voltage divider network of passive resistors.

Peripheral
A device that performs a function and is external to the system board. Peripherals include displays, disk drives, and printers.

Platform
A basic design from which a series…

Disk Doctors Mac Data Recovery software recovers lost and deleted data from HFS+, HFSX file systems on Mac OS X 10.4 and above, which includes LEOPARD.

Recover Lost Data When:

• A volume has been formatted or reformatted
• Volume is inaccessible after re-partitioning or any sort of corruption causing inaccessibility to the volume
• Volume is not getting mounted
• Files and folders are accidentally deleted, Apple partition map is corrupted
• Apple catalog file is corrupted
• Drive has been initialized
• Disk verify and repair fails
• Any sort of corruption causing inability to boot your operating system

Disk Doctors Mac Data Recovery Software Features:

• Simple and intuitive user interface
• Supports recovery

…

MB (Megabyte)
One megabyte as 1,000,000 (one million) bytes.

MFM (Multiple Frequency Modulation)
A method of encoding analog signals into magnetic pulses or bits.

MR Heads (Magneto-resistive Heads)
MR heads were developed to increase area density and improve drive performance. MR heads use separate read and write elements, as opposed to traditional inductive thin-film read-write heads. MR heads use an inductive element for writing data, and a separate magneto-resistive element for reading information. The read element has a magnetically sensitive material that detects data recorded on the magnetic disk surface. MR head construction results in a stronger signal than that produced by inductive thin-film read-write heads, which permits it to read higher area density data. Since the…