appendix a

Connecting SCSI Drives

SCSI hard drives are the recommended recording media for Pro Tools|HD systems on Windows, and can also be used with Pro Tools on

Macintosh.

Although Pro Tools will let you record to your system drive, this is generally not recommended. Performance for recording and playback on system drives is sometimes worse than on non-system drives, resulting in lower track counts and fewer plug-ins.

Be aware that recording to your system drive can quickly use up available hard drive space. This can negatively affect system stability and the performance of all applications including Pro Tools.

For the most current information on hard drive requirements and recommendations, see the compatibility pages on the Digidesign Web site

(www.digidesign.com/compato).

SCSI Requirements

Digidesign recommends qualified SCSI hard drives and a qualified SCSI host bus adapter

(HBA) card or (on Windows systems) a qualified built-in SCSI HBA connector on the motherboard.

For a list of qualified SCSI hard drives and SCSI

HBA cards, refer to the Digidesign Web site

(www.digidesign.com/compato).

Software RAID is not supported for audio drives.

Appendix A: Connecting SCSI Drives 99

SCSI Cables

Use shorter SCSI cables to improve reliability.

Table 1 provides guidelines for maximum cable lengths according to SCSI type.

In the following table, the maximum cable length includes all cables used in the chain, not just point-to-point connections.

Table 1: Maximum cable length and number of drives supported according to SCSI type

SCSI type and transfer rate maximum cable length maximum # of drives

3 meters 8 Fast SCSI

10 MB/sec

Wide SCSI

20 MB/sec

3 meters 16

3 meters 5 Ultra SCSI

20 MB/sec

(8-bit narrow)

Ultra SCSI

40 MB/sec

(16-bit wide)

Ultra SCSI

20 MB/sec

(8-bit narrow)

Ultra SCSI

40 MB/sec

(16-bit wide)

Ultra2 SCSI

Low Voltage Differential (LVD)

80 MB/sec

3 meters

1.5 meters

1.5 meters

1.2 meters

5

6–8

6–8

16

Distribute Audio Across Multiple Drives

For best recording and playback performance, don’t record and play back all audio files in a session from the same drive. Instead, use

Pro Tools Disk Allocation features to distribute audio files between multiple drives. See the

Pro Tools Reference Guide for details.

Separate Video and Audio Files

If you are working with QuickTime, movie files must reside on a different SCSI bus than audio files. If audio files reside on disks connected to a

SCSI HBA card, video data should reside on drives connected to a different SCSI bus.

Dual-Channel SCSI HBA Cards

If you use a dual-channel SCSI HBA card, allocate audio files equally to drives connected to each of the two busses on the card for optimal performance.

If using video files, make sure to put your video files on one bus and audio files on the other bus.

Connecting SCSI Drives

To connect an external SCSI drive:

1 Turn off power to both the computer and the hard drive.

2 Attach a SCSI cable from the SCSI port of the hard drive to the SCSI port of the SCSI HBA card or computer.

3 Secure the cable’s connectors to the hard drive and computer.

4 Connect additional drives by daisy-chaining from one drive to another. Keep cable lengths to a minimum (see Table 1).

100 Pro Tools|HD Getting Started Guide

5 Verify that the last SCSI device in the chain is

properly terminated. (See “SCSI Termination” on page 101.)

6 Attach power cables to the hard drives.

SCSI accelerator card

SCSI Termination

Your computer’s SCSI chain must be properly terminated or your system will not function correctly. Only the last device on the chain should be terminated using the termination type recommended by the hard drive manufacturer.

The drive should use either an external terminator plug or have its internal terminators enabled. If you are using a terminator plug, Digidesign recommends that you purchase and use an

active terminator.

Do not enable internal termination and install an external terminator plug on the same drive. This will cause SCSI errors. See your hard drive’s documentation for information on which type of termination it uses. to SCSI hard drive

Connecting a SCSI cable to a SCSI HBA card to SCSI accelerator card

Connecting an external SCSI hard drive

Quick Formatting SCSI Drives

Macintosh Requirements

On Macintosh systems, SCSI hard drives used for audio recording on TDM systems must be formatted (or initialized) for either the HFS+ or

HFS file system (HFS+ is recommended). Drive partitions of up to 2 terabytes (2000 gigabytes) can be used.

TDM systems require that you use the Apple

Disk Utility for all drive formatting and partitioning. Only one disk utility should be used for all drives in a system.

Appendix A: Connecting SCSI Drives 101

Windows XP Requirements

SCSI hard drives used for audio recording on

TDM systems must be formatted as NTFS or

FAT32. FAT32 drive partitions have a limit of

2 terabytes (2000 gigabytes), whereas NTFS drive partition sizes are almost limitless.

TDM Windows systems require that you use Microsoft Windows Disk Administration software for drive formatting and partitioning. Use only one disk utility for all drives in a system.

Initializing a Macintosh Drive

To initialize a new Macintosh drive:

1 Turn on your hard drives, computer, and any other peripherals.

2 Use the Apple OS X Disk Utility to initialize and partition any new hard drives.

For details on using disk formatting utilities, refer to the drive’s documentation and

Apple online documentation.

Initializing a Windows Drive

To format a new Windows drive:

1 Turn on your hard drives, computer, and any other peripherals.

2 Use Microsoft’s Disk Management software, located in the Administrative Tools Control

Panel under Computer Management > Storage.

Refer to your Windows documentation or help for information on how to use the Disk Management software.

General Hard Drive

Maintenance

If you are using Macintosh drives on Win-

dows systems, refer to“Using Macintosh

Drives on Windows Systems” on page 104.

Formatting Drives

There are two different types of formatting: high-level formatting (initialization) and lowlevel formatting.

Digidesign does not recommend low-level formatting audio drives.

Initializing a drive replaces the drive’s directory, volume partition map and drivers. Information about the drive is created and drivers that communicate this information to the host CPU are installed. The drive itself is not erased, nor is verification performed.

When to Initialize a Drive

It is generally necessary to initialize a hard drive in one of the following cases:

◆ If a new drive is being prepared for use on a computer for the first time and the drive is not already initialized.

◆ If you suspect that the directories containing the drive’s information have become corrupted.

◆ If a drive is being changed from one platform to another. For example if you are switching from a Macintosh to a Windows-based system, or from a Windows to a Macintosh-based system, the drive must be initialized for the new operating system.

102 Pro Tools|HD Getting Started Guide

Partitioning Drives

Partitioning divides a physical drive into multiple, logical volumes, almost as if you were creating virtual hard drives. Partitions can then be formatted with the appropriate file system

(NTFS for Windows, HFS+ for Macintosh).

Windows XP allows drives formatted with the NTFS or FAT32 file systems to be seen as whole volumes. Single Pro Tools audio files cannot exceed 2048 MB in size.

Mac OS allows drives larger than 4096 MB to be seen as whole volumes. Drives must be initialized with a disk utility that recognizes the 2 terabyte limit. Single Pro Tools audio files cannot exceed 2048 MB in size.

Seek Times on Partitioned Drives

Seek times are actually faster on partitioned drives (assuming that reads and writes are performed on a single partition), since the heads only have to seek within the partition boundaries, rather than the whole capacity of the drive.

Smaller partitions perform faster than larger partitions, but this comes at the expense of contiguous storage space. When you partition a drive, you will need to find the compromise that best suits your performance and storage requirements.

Avoid distributing audio files within a session over different partitions on the same drive since this will adversely affect drive performance.

Avoiding File Fragmentation

For maximum recording and playback efficiency, data should be written to your hard drive in a contiguous fashion—minimizing the seek requirements to play back the data. Unfortunately, your computer can’t always store the sound files in this way and must write to disk wherever it can find space.

In multitrack recording, audio tracks are written in discrete files, spaced evenly across the disk.

While fragmentation of individual files may be zero, the tracks may be far enough apart that playback will still be very seek-intensive. Also, the remaining free space on the disk will be discontiguous, increasing the likelihood of file fragmentation on subsequent record passes.

Increased fragmentation increases the chance of disk errors, which can interfere with playback of audio, and result in performance errors.

On Windows, to avoid fragmentation, format drives with higher cluster sizes (such as

32K).

On Macintosh, if Norton Utilities is used, it must be Norton Utilities v4.0 or later to ensure compatibility with HFS+ drives.

Appendix A: Connecting SCSI Drives 103

Optimizing (Defragmenting) Drives

To prevent fragmentation, you can optimize your drive, which rearranges your files into a contiguous format. Most optimizing software lets you run a check on a drive to find out the percentage of fragmentation. If your drive shows moderate to heavy fragmentation, you should consider optimizing it.

If you use your system for intensive editing, or if you frequently delete audio or fade files from your hard drive, you may need to optimize your drives on a weekly basis, or even every few days, since it doesn’t take long for even a large hard drive to become fragmented.

Backing Up Data Before Optimizing

Since your files will be rewritten by the optimization process, always make a backup copy of the data on your hard drive before you optimize it. You should also use a hard drive utility to find and repair any problems before optimizing data or re-initializing your drives. If there is any damage to your hard drive's directories prior to optimizing, serious data loss may result.

Using Macintosh Drives on

Windows Systems

Pro Tools for Windows lets you record and play back sessions directly from a Macintosh-formatted (HFS+) drive connected to a Windows system. This functionality requires that all Macintosh session and audio files be stored on

Macintosh-formatted drives.

To mount HFS+ drives on a Windows system, you can use the MacDrive utility. An installer for the demo version of MacDrive is included with Pro Tools.

For details on sharing sessions between

Macintosh and Windows systems, see the

Pro Tools Reference Guide.

Formatting and Maintaining HFS+

Drives

To format and partition any drives as HFS+, connect the drives to a Macintosh computer and use the Apple OS X Disk Utility.

104 Pro Tools|HD Getting Started Guide