2025-05-19

Hard Disk Drive Resource Links (Linux System)

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http://www.nyx.net/~sgjoen/disk.html
This document describes how best to use multiple discs and partitions for a Linux system. Although some of this text is Linux specific, the general approach outlined here can be applied to many other multi tasking operating systems.

http://tldp.org/HOWTO/Hard-Disk-Upgrade/index.html
This document describes how to copy a Linux system from one hard disc to another.

http://tldp.org/HOWTO/Partition-Rescue/index.html
This document describes how to rescue your Linux partition if MS-DOS deleted it.

http://tldp.org/HOWTO/Partition/index.html
This document explains how to plan and layout disc space for a Linux system. It talks about disk hardware, partitions, swap space sizing and positioning considerations, file systems, file system types, and related topics. The intent is to teach some background knowledge, not procedures.

http://tldp.org/HOWTO/Large-Disk-HOWTO.html
This document covers how to configure disc drives with more than 1024 cylinders for use with Linux.

http://tldp.org/HOWTO/Root-RAID-HOWTO.html
This document provides a cookbook for creating a root mounted RAID file system and companion fallback rescue system using Linux initrd. There are complete step-by-step instruction for both raid1 and raid5 md0 devices. Each step is accompanied by an explanation of its purpose. Included with this revision is a generic Linux initrd file which may be configured with a single three line /etc/raidboot.conf file for raid1 and raid5 configurations.

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Advanced Host Controller Interface (AHCI)

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Advanced Host Controller InterfaceAHCI (Advanced Host Controller Interface) is present on newer Intel chipsets. AHCI mode is enabled in the BIOS where 3 settings are commonly available: IDE, AHCI, and RAID. The last two (AHCI and RAID) require a floppy disk with the driver that can be introduced into the operating system installation through F6. Otherwise, the hard disks won’t be detected.

AHCI mode has 3 main advantages:

  • Supports NCQ (Native Command Queuing) allowing SATA drives to accept more than one command at a time and dynamically reorder the commands for maximum efficiency.
  • Supports hot plugging of devices.
  • Supports staggered spin ups of multiple hard drives at boot time.

When it comes to performance, there really isn’t a big difference in using AHCI.

Note: If you installed Windows in IDE mode (which means that you didn’t use F6 and supply a driver disk), then simply changing the BIOS setting to AHCI mode and rebooting will cause Windows to fail and will require a repair install. Most people are advising to reinstall Windows if you want AHCI enabled. (More information on AHCI)

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Controllers verified to provide visible RAID volumes greater than 4 TB

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The list of controllers below has been verified to provide visible RAID volumes greater than 4 TB.

3Ware 9550SXWin 2003
3Ware 9690PLWin 2003
RHEL 5 U 2
Adaptec 1420SAWin 2003
Areca ARC-1220MLWin 2003
RHEL 5 U 1
HighPoint 2220Win 2003
HighPoint 3220Win 2003
Intel ICH8RWin Vista x86
Win Vista x64
Win XP x64
Intel ICH9RWin Vista x86
Win Vista x86
Win XP x64
Silicon Image SIL3124Win 2003
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Seagate Hard Drive Families (Part II)

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Seagate Hard Drive FamiliesSeagate Technology is one of the world’s largest hard drives and storage solutions manufacturer. Incorporated in 1978 as Shugart Technology, Seagate is currently incorporated in Dublin, Ireland and has its principal executive offices in Scotts Valley, California.

The new FreeAgent ® GoFlex™ Family
Enjoy reliable, secure storage. Unique plug-and-play design allows easy upgrading of interfaces for faster transfer speeds on your PC or Mac ® computer. Access stored content on your network, on your TV–and everywhere you go.

    • GoFlex™ Ultra-portable Drive

This ultra-versatile, ultra-portable drive makes it ultra-easy for you to store, back up and encrypt your files anytime, anywhere

 

  • GoFlex™ Pro Ultra-portable Drive
    This ultra-portable drive includes the GoFlex Dock plus premium backup and encryption software
  • GoFlex™ Desk External Drive
    The high-capacity storage you need that’s easy to upgrade and easy to use

 

Momentus® Laptop Hard Drives
Seagate® Momentus® hard drives — rising to the call of a faster, safer, more reliable mobile computing world

  • Momentus® XT Solid State Hybrid Drives
    The Momentus XT drive offers hybrid storage with Adaptive Memory™ processing, enabling the drive to deliver capacities up to 500GB and SSD-like performance.
  • Momentus® Hard Drives
    The Momentus drive offers innovative options, capacities to 750GB, two performance speeds and significant feature options: self-encryption, G-Force Protection™ technology and FIPS 140-2 for government-approved security. (Options not available in all countries)
  • Momentus® Thin Hard Drives
    The Momentus Thin drive is the world’s first 7mm, 2.5-inch form factor drive. It is specifically created for slim computing. The Momentus Thin drive is designed to enable increased profitability and differentiate solutions for Seagate OEMs and integrators.

Seagate® Replica™
Never forget to back up your files ever again. Now it’s easy and automatic.

Seagate® 2.5-Inch Enterprise SSD and HDD Drives
The Seagate® 2.5-inch enterprise drive families offer the best combination of reliability, performance and business efficiency.

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Tips For Replacing A Hard Drive From A Failed RAID

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Tips For Replacing A Hard Drive From A Failed RAIDThere are some items to consider when replacing a hard drive from a failed RAID. If you are building a new RAID, then all hard drives in the array should be the identical model if at all possible. However, if you must replace a failed hard drive, it can sometimes be difficult to find the same model if that model is out of production.

Below are some tips to follow when selecting a replacement:

Keep in mind that the controller may or may not allow different models in a RAID, so check the RAID controller documentation.

Product life: What is the expected life of the remaining drives? If the other drives are approaching the end of their useful life, then it may be time to replace the entire RAID.

Capacity: The replacement drive should be the same or higher capacity than the original drive. Do not just look at the capacity on the box, since a few megabytes could make the difference between whether the drive will work or not.

(You should check the number of LBAs (or sectors) on the hard drive. Some RAID controllers will allow you to substitute larger drives if the exact capacity is not available, while other controllers require an exact match. Check with the controller manufacturer if the documentation doesn’t make it clear!)

Performance: The replacement drive should match the performance of the remaining drives as closely as possible. If your failed drive was 15,000 RPM, avoid replacing it with a 10,000 RPM drive. RAID arrays depend on the timing between drives to write data. Thus, if one drive doesn’t keep up, it may cause the entire array to fail or at least experience irritating problems.

Interface: Make sure the replacement drive uses the same type of interface connection as the failed drive. If the failed drive used a SCSI SCA (80-Pin) interface then don’t try to replace it with a 68-pin SCSI interface. With Seagate products the last two digits of the model number indicate the interface. For example: LW = 68-Pin, LC = 80-Pin.

The 80-pin LC drives are hot-swappable with backplane connections.

Cache Buffer: It is recommended that the cache buffer for each drive be the same value.  Most RAID controllers will consider drives with mismatching cache buffers to be ineligible for addition to a striped or parity array.

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Tips for selecting Hard Drives for use in a SCSI/SATA RAID Configuration

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Tips for selecting Hard Drives for use in a SCSI/SATA RAID ConfigurationMost SCSI and SATA RAID controllers will accept different kinds of hard drives. The hard drives should match in capacity points and rotational (RPM) speed. At best, all drives in an array will be identical–at the same firmware revision level.

RAID can be used with any size hard drive. The smallest capacity drive will determine the largest logical volume size for all drives in the array.

Whenever possible, select drives from an approved vendor drive compatibility list. This ensures that the hard drive is tested, and should function reliably with your SCSI or SATA RAID controller. Untested configurations can possibly work as well. But for best results, select only tested and compatible drives for your SCSI or SATA RAID controller. Most SCSI or SATA controller vendors publish a hard drive compatibility matrix on their web site.

Looking for legacy hard drives? CUE Technologies Inc

Pricewatch.com is a service to allow retailers to advertise their prices in real time, for locating and supplying most any type and brand of computer product, including hard-to-find items.

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RAID Controllers

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RAID Controllers What is a RAID Controller?

A disk array controller is a device which manages the physical disk drives and presents them to the computer as logical units. It almost always implements hardware RAID, thus it is sometimes referred to as RAID controller. It also often provides additional disk cache.

A disk array controller name is often improperly shortened to a disk controller. The two should not be confused as they provide very different functionality.

RAID Controller History:

While hardware RAID controllers were available for a long time, they always required expensive SCSI hard drives and aimed at the server and high-end computing market. SCSI technology advantages include allowing up to 15 devices on one bus, independent data transfers, hot-swapping, much higher MTBF.

Around 1997, with the introduction of ATAPI-4 (and thus the Ultra-DMA-Mode 0, which enabled fast data transfers with less CPU utilization) the first ATA RAID controllers were introduced as PCI expansion cards. Those RAID systems made their way to the consumer market, where the users wanted the fault-tolerance of RAID without investing in expensive SCSI drives.

ATA drives make it possible to build RAID systems at lower cost than with SCSI, but most ATA RAID controllers lack a dedicated buffer or high-performance XOR hardware for parity calculation. As a result, ATA RAID performs relatively poorly compared to most SCSI RAID controllers. Additionally, data safety suffers if there is no battery backup to finish writes interrupted by a power outage.

How to Choose a RAID Controller?

New RAID levels, technologies and interfaces make choosing a RAID controller more than just a choice between price and performance. These top tips provide valuable insight to help ensure that you get exactly the right controller to suit your specific data protection needs.

1. Choose the correct bus interface for your needs — forward- or backward-compatibility.

PCI-X has the advantage of being backwardly compatible with the older PCI interface. But it is parallel and half-duplex bidirectional, and the bus runs only as fast as the slowest device. PCIe is the new forward-looking standard, and is intended to cope with the performance and scalability demands for at least the next decade. PCIe has the advantages of being serial, full-duplex bidirectional, and devices are able to independently negotiate the bus speed.

2. Find an easy-to-use Management Interface.
3. Which RAID level?
Considering the factors: Cost of disk storage, Data protection or data availability required, Performance requirements

4. RAID level migration
Consider how complex the process is to migrate your data from your current RAID to your new one and consider whether RAID level migration is something you need.

5. How much more data capacity will you need.

6. A limitation of SATA
The SATA infrastructure allows for Port Multipliers, but they have drawbacks – they can’t be daisychained, limiting their flexibility and expandability; they only support one active host connection at a time, significantly degrading effective throughput and allowing for potential
misidentification of drives.

7. Getting locked in to your Operating System
Your choice of RAID controller shouldn’t restrict either your choice of OS, or restrict the speed at which you can obtain an OS upgrade.

8. Reliability of the RAID code

9. Hardware or software RAID?
The difference between hardware and software RAID isn’t just the price.With hardware RAID, the calculations are carried out by the RAID controller, with software RAID they take place on the server’s CPU. So, if the RAID calculations are fairly simple, say RAID 1 or RAID 10, and the server is fairly powerful, using software RAID shouldn’t be much of a problem. But with more
complex RAID level calculations (RAID 5EE or RAID 6 for example), using hardware RAID can be beneficial because the RAID performance is not compromised by the server’s workload, nor are applications on the server compromised by the RAID workload.With hardware RAID, the RAID functionality is also independent of the OS, and the simple HBA drivers required for a hardware RAID controller are usually available as part of the OS distribution. Also, if it has a battery, hardware RAID can run in write-back mode, adding another level of data protection.

10. Ensure the products you purchase have the support you need

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Top 10 Most Popular Flash Memory Cards on Amazon.com

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Top 10 Most Popular Flash Memory Cards on Amazon.com A flash memory card is an electronic flash memory data storage device used for storing digital information. They are commonly used in many electronic devices, including digital cameras, mobile phones, laptop computers, MP3 players, and video game consoles. They are small, re-recordable, and they can retain data without power.

Flash memory cards types: Secure Digital (SD), MiniSD Card, CompactFlash (CF), Memory Stick (MS), MultiMediaCard (MMC) xD-Picture Card (xD) and SmartMedia (SM).

SD cards are now the most popular flash media type and getting bigger (up to 32GB) and faster (up to 150x speed and beyond) all the time!

4GB Flash Memory Cards:

Transcend 4 GB Class 6 SDHC Flash Memory Card (TS4GSDHC6E)
(Price on Amazon.com: $6.75)

Kingston 4GB Class 4 SDHC Flash Memory Card (SD4/4GBET)
(Price on Amazon.com: $6.88)

Sony 4GB Memory Stick PRO Duo Flash Memory Card (MSMT4G)
(Price on Amazon.com: $10.58)

Sandisk 4GB Secure Digital SDHC Flash Memory Card (SDSDB-4096)
(Price on Amazon.com: $7.08)

8GB Flash Memory Cards:

Transcend 8GB Class 6 SDHC Flash Memory Card (TS8GSDHC6)
(Price on Amazon.com: $13.50)

SanDisk 8GB Class 2 SDHC Flash Memory Card (SDSDB-8192)
(Price on Amazon.com: $7.16)

Kingston 8GB microSDHC Class 4 Flash Memory Card (SDC4/8GB)
(Price on Amazon.com: $9.55)

16GB Flash Memory Cards:

Transcend 16GB Class 10 SDHC Card (TS16GSDHC10)
(Price on Amazon.com: $27.84)

SanDisk 16GB microSDHC Flash Memory Card (SDSDQ-016G)
(Price on Amazon.com: $23.99)

32GB Flash Memory Cards:

Transcend 32GB Ultimate Speed SDHC Class 10 Flash Memory Card (TS32GSDHC10)
(Price on Amazon.com: $49.59)

These are the ratings of some currently available cards:

  • Class 0 cards do not specify performance, which includes all legacy cards prior to class specifications.
  • Class 2, 2 MB/s, slowest for SDHC cards
  • Class 4, 4 MB/s
  • Class 6, 6 MB/s
  • Class 10, 10 MB/s

The Speed Class Rating is the official unit of speed measurement for SD Cards, defined by the SD Association. The Class number represents a multiple of 8 Mb/s (1 MB/s), and meets the least sustained write speeds for a card in a fragmented state.

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Compact Flash FAQs

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Compact Flash What is Compact Flash?

CompactFlash is the world’s smallest removable mass storage device. First introduced in 1994 by SanDisk Corporation, CF TM cards weigh a half ounce and are the size of a matchbook. They provide complete PCMCIA-ATA functionality and compatibility. Compact Flash is a small, removable mass storage commonly used in digital cameras.

Where will CompactFlash be used?
Several leading consumer electronics companies, including the CFA’s roster of founding members, are designing CF technology into next-generation products being developed for mass markets. The CFA expects CF technology will be widely used in such products as portable and desktop computers, digital cameras, handheld data collection scanners, cellular phones, PCS phones, PDAs, handy terminals, personal communicators, advanced two-way pagers, audio recorders, monitoring devices and set-top boxes. CF technology offers all of these applications new and expanded functionality while enabling smaller and lighter designs.

What is the difference between Type I and Type II?
Type I is 3.3mm thick, while Type II is 5mm thick. A CF Type II device will not fit in a Type I slot.

How do I format my Compact Flash drive?
Formatting a Compact Flash drive can be accomplished several ways. The most common method of formatting a Compact Flash drive is within the device in which the Compact Flash drive will be used. This will ensure a device compatible format and the best overall performance.

How do I interface the CF drive with my PC or Mac?
Compact Flash drives are connected to desktop/laptops computers through flash memory card readers. A typical card reader will contain multiple flash memory slots to accommodate the different types of memory. The card readers are most commonly attached to the computer via a USB or IEEE 1394 (FireWire) interface cable.

Do I need drivers for my OS?
Compact Flash drives do not require drivers. However, when the drive is attached through a card reader, the proper drivers for the card reader must be installed before the drive can be accessed.

Can I use this in my PDA? Does this drive require drivers?
The Compact Flash drive can be used in any PDA that will support Compact Flash Type II drives with high capacity. This is not a supported hardware environment.

While many PDA operating systems do not require drivers, some of the older operating systems, such as Windows CE, will require a driver before the drive can be accessed.

Can I install an OS onto this drive?
Depending on the operating system in use, it may be possible to install an OS onto the Compact Flash drive. Since this is not the intended purpose of the drive, the performance may be less than desired and no support will be provided.

What is the speed of my Compact Flash card?
Solid state CF memory cards are differentiated by a speed number:

Compact Flash Speeds
Speed
Kbytes/s
Mbytes/s
1
150
0.15
4
600
0.6
12
1800
1.8
24
3600
3.6
40
6000
6
60
9000
9
80
12000
12

What is the difference between FAT16 and FAT32, why do cards greater than 2GB require FAT32?
File Allocation Tables (FAT) are like a table of contents to your data. Prior to Windows 98, 16-bit FATs limited partitions to 2.1 Gbytes. The newer 32-bit FAT is capable of huge partitions up to two Tbytes (terabytes). Many digital cameras only support 16-bit FAT (FAT), newer cameras and high-end professional cameras usually support 32-bit FAT (FAT32). Check your camera’s manual or support information to determine if your camera supports FAT32 (memory larger than 2.1Gbytes).

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What risks do viruses pose to the data on a hard drive?

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What risks do viruses pose to the data on a hard drive? When it comes to data storage, viruses can be divided into two basic categories:

  • Viruses that delete data
  • Viruses that corrupt data

Viruses that delete data will tell the operating system (such as Windows) to flag files as being deleted. The data itself becomes unavailable but it still exists on the platters until it’s overwritten. This data is recoverable using Data Recovery Softwares designed to perform data recovery which will scan the platters and mark recognizable files as not deleted, effectively restoring them to the directory structure.

Viruses that corrupt data are the most dangerous because they overwrite files with garbage data and then possibly flag them as deleted. This makes the data unrecoverable.

In either case, it is very important to have antivirus software running on any machine whether it’s connected to the internet or not (viruses can be propagated from CDs, floppies, and other storage mediums) and keep a backup of any critical data on a removable storage device which will help prevent viruses from propagating to your backup.

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