Videography - April 1997

Digital Storage Saves Digital Video
By Sheldon Liebman

This month, Videography is spotlighting the Digital Storage industry. But what exactly is Digital Storage and how does it compare to Digital Video? Depending on how familiar and comfortable you are with the worlds of computers and video, these terms can be used to describe many different things.

One definition of Digital Storage is related to Still Store or Frame Store equipment. These devices save individual frames of video in a digital format so that they can be quickly recalled. Depending upon exactly what type of device you are using, you may be able to name each image and have access to it from a type of database. Or you may simply refer to an image as Frame 42.

Closely related to Still Stores is the traditional form of Digital Disk Recorder. Often used as a standalone piece of equipment, DDRs save video clips in a digital format and allow you to play them back one at a time or in a real-time sequence.

Another type of Digital Storage is the use of computer-style Magnetic Tape to store frames or sequences of video. A few years ago, this was the method used to save or back up the contents of DDRs.

Since videotape is also a form of magnetic tape, the D1 video format can also be considered a form of Digital Storage. Technically, we can call every D1 videotape a Digital Storage device, although that probably isn't the first thing people think of when they hear the term.

All of these forms of storage are used in a traditional video environment. When you move into a computer video environment, however, even if the ultimate goal is the same, everything starts to change.

A Whole New World
No matter how hard they try, computer hardware and software companies have still not been able to develop "open" systems and products that are immediately comfortable and familiar to traditional video professionals. Mostly, this revolves around the intrusion of the operating system into virtually every task that must be accomplished. Frames and Clips are replaced by Files and Directories. Tapes are replaced by Disks. For many people, learning to understand these differences is a daunting assignment.

Closely related to the operating system is the total performance of the computer system. Obviously, things like processor speed are important, but so is the interface between the processor and every other part of the computer system. Specifically, the speed with which all the different devices in the system can communicate is crucial.

Over the past few years, the number of ways that devices can communicate has increased significantly. Once, there was IDE on the PC side and SCSI on the Mac and workstation side. Today, we have Enhanced IDE (EIDE) and Ultra SCSI, plus brand new formats like Fibre Channel, FireWire, HIPPI, SSA and the Universal Serial Bus (USB). We've covered many of them and will continue to cover them in the future, but trying to understand the differences between them is almost a full time job in itself.

In every case, though, certain key issues come up. First is the capacity of the disks that are being used. It doesn't matter how fast they are if they can't hold enough information. Second is whether the storage is planned for standalone or network use.

When computer based systems were first introduced, just having them available was revolutionary enough. Getting them to talk to each other and share information was almost too much to hope for. Today, the phrase "no man is an island" has a special meaning for production professionals. In many cases, the ability to move data quickly between systems or to have multiple systems accessing the same information isn't just a wish, it's a requirement.

The third consideration is the total throughput between the storage system (or sub-system) and the computer. This is typically based on two factors - the speed of the disks themselves and the speed of the interface. Increasing the speed of the disks often involves merging multiple physical disks into a single logical disk through the use of a disk array. The speed of the interface depends on which one you use and what type of computer it's going into. For example, the latest version of SSA claims up to 80 MegaBytes per second (MBps) of throughput while Ultra SCSI is capable of approximately half that, or 40 MBps.

A fourth factor, which may not necessarily be a major one, is the cost of the storage and interfaces. Compared to the costs of a total system, the digital storage portion may not be a major expense, but it's certainly not free. And you also have to add in the costs of interface cards and cabling. In a network storage situation, there is the benefit of sharing the costs among a number of stations. But the price of fast networking technology can get pretty high.

Finally, there is the issue of managing all the data on these disks, which in some cases can hold an incredible amount of information. A CentricStor disk array from Siemens Nixdorf, for example, can be configured with over 100 GigaBytes (GB) of storage. If full resolution, uncompressed video takes up 30 MB for every second of video stored, 100 GB can hold about an hour of footage.

In most cases, the video is compressed at least 5:1 before it is stored, resulting in 5 hours of footage on this size array. Keeping track of all this information is not a simple thing to do and many manufacturers are taking significant steps toward creating a method to manage these assets. The first company that finds a way to sort and catalog this information so video professionals are comfortable is sure to gain a significant advantage in the marketplace.

Part of the reason for this is that these Digital Storage solutions are just one piece of the digital video puzzle. Unlike DDRs or Still Stores, these are not video devices on their own. They are simply storage systems that attach to standard computers. The contents of the files may have video information, but to the system, they're just big files. There must be other hardware and software in the system that is capable of bringing video into the system, manipulating the video information contained in the files, and creating an output video stream at the end. Without these additional pieces, you really do just have a lot of big files.

Going to the Digital Store
Creating a complete list of the companies that supply Digital Storage solutions is not an easy thing to do. There are the companies that make the disks, the companies that build arrays, the companies that make the interfaces and the companies that market entire solutions. Just deciding which companies qualify as supplying video storage solutions is a difficult thing to do. At the lowest end, you can create highly compressed video using the standard hard disk that comes with a Pentium computer. At the highest end, you've got systems that are capable of supporting multiple simultaneous streams of uncompressed video.

Which companies truly serve our market? A good place to start is with the companies that have identified digital video as a market for their products. Following is a partial list of the players in this arena with information about what they have to offer. This is a very dynamic market, however, so if you're shopping for storage, be sure to double-check your (and our) information.

ATTO Technology
In January, ATTO (Amherst, NY) started shipping its AccelNet product, a high performance SCSI-based hub that allows multiple host systems to have shared access to SCSI peripheral devices. AccelNet is compatible with PCs, Macs and Workstation systems and supports sustained transfer rates of up to 20 MBps.

At this month's NAB show, ATTO introduced a new product, the ExpressPCI Dual-Channel host adapter and RAID Solution Kit. The new product supports Ultra SCSI transfer rates of up to 40 MBps using ATTO's exclusive Advanced Data Streaming technology.

At this month's NAB, Ciprico, Inc. (Plymouth, MN) demonstrated a significant new technology. Working with SGI, Brocade Communications, Prisa Networks and the University of Minnesota, the company showed what it claimed was the first Fibre Channel based, direct network attached storage. The demonstration used Ciprico's 7000 Series Fibre Channel RAID disk arrays connected directly to SGI workstations using Brocade switches and Prisa adapters. Software developed at the University of Minnesota allows the 7000 arrays to communicate with the workstations.

In addition to their Fibre Channel arrays, Ciprico also markets Ultra SCSI disk arrays. At NAB, the company introduced the 6900 disk array, which is a five-drive disk array for customers who require real-time speeds but not the capacity of Ciprico's nine-drive, 6910 array.

La Cie
La Cie, Limited (Beaverton, OR) offers the Speed2 (pronounced Spee-Dee-Two) video solution for fast, scalable disk access from PCI-based Power Macintosh computers. Speed2 utilizes SSA technology to provide up to 80 MBps throughput on a two-way loop that can be scaled to include any combination of up to 128 devices.

Today, the software included with Speed2 is designed for access from a single workstation, but La Cie is developing driver software that will allow shared access to volumes on an SSA loop. Access control is at the driver level, so all users will have access to SSA volumes just like any other disk drive.

MegaDrive Systems
Last year, MegaDrive (Chatsworth, CA) began shipping their Aria line of Fibre Channel disk arrays. Aria supports up to 92 GB of storage per enclosure with the ability to daisy chain multiple enclosures together for multi-TeraByte (TB) capacity. According to the company, Aria supports 200 MBps throughput to accommodate multiple simultaneous video streams.

MegaDrive also offers the EV-1000 RAID system which is available in either Ultra SCSI or Fibre Channel configurations. Using 23 GB disks, the EV-1000 supports up to 805 GB of on-line data storage. In the Ultra SCSI version, the system is capable of throughput up to 80 MBps. The EV-1000 supports Silicon Graphics IRIX, Apple Macintosh OS, Microsoft Windows NT, Sun Microsystems Sparc and IBM RS/6000 A/IX environments.

MicroNet (Irvine, CA) sells the DataDock family of storage and transport systems. DataDock products can be configured with virtually any type of drive or drive array, including Optical, CD-Recordable and even removable drives like the Iomega Zip and Jazz. The standard DataDock is a two bay system and the DataDock 7000 is a seven bay, high capacity, high performance RAID system.

DataDock is compatible with all popular operating systems and with virtually any CPU using a SCSI interface. It can use Fast SCSI, Fast/Wide SCSI, Ultra SCSI or Ultra/Wide SCSI with a capacity for hundreds of GigaBytes of storage on a single SCSI bus.

Last November, Micropolis (USA) Inc. (Chatsworth, CA) introduced a 9.1 GB version of its popular Tomahawk AV Gold disk drive. By adding this higher capacity drive to the already existing 4.5 GB version, Micropolis gave some options to single system users who need high-speed throughput for audio/video applications. Both Tomahawk disks use an Ultra SCSI interface to provide performance of up to 10 MBps from a single drive system.

This past February, MountainGate (Reno, NV) announced the release of CentraVision, the first Fibre Channel solution to be delivered to the video industry. CentraVision is a complete solution, including Fibre Channel disk arrays, hubs, control software and all necessary host adapters and connectors. According to the company, it has been optimized for broadcast and post-production, allowing multiple workstations in a facility to be linked on the fastest network available with large storage capacities that are required for digital video.

CentraVision operates at speeds up to 100 MBps (200 MBps full duplex) and supports storage capacity from 36 GB to more than 1 TB. The CentraVision hubs can support nine devices on a Fibre Channel network, which can be either workstations, disk arrays or additional hubs. By linking hubs together, up to 126 total devices can be connected. CentraVision for the Mac is available now with SGI IRIX and Windows NT releases scheduled for later this year.

ProMax Systems
Macintosh users looking for fast disk arrays up to 70 GB can purchase a variety of configurations from ProMax Systems, Inc. (Irvine, CA). Using Ultra SCSI host adapters, ProMax offers systems containing from 2 - 8 Seagate disks with performance up to 60 MBps.

RaidTec Corporation
RaidTec (Roswell, GA) markets a variety of RAID array products using both SCSI and Fibre Channel interfaces. Most recently, the company introduced FlexArray UltraRAID, an Ultra SCSI RAID subsystem that supports up to 126 GB of storage capacity. The FlexArray UltraRAID subsystem consists of the UltraRAID PCI-based caching controller and a FlexArray T subsystem enclosure. Together, these products deliver up to 40 MBps throughput.

Late last year, RaidTec introduced a TeraByte Fibre Channel RAID storage system comprised of the company's FibreArray subsystem, FibreRAID controller and 112 Fibre Channel drives. According to the company, this is the only complete Fibre Channel RAID solution available from a single vendor.

Siemens Nixdorf
Last month, we wrote about Design Media in San Francisco, who recently installed an SSA network including the CentricStor-F Disk Drawer from Siemens Nixdorf (Munich, Germany). CentricStor-F is available as either a Desktop, Drawer or Tower configuration supporting up to 24 GB, 48 GB or 96 GB total storage, respectively. Multiple models can be configured in a single SSA loop to provide even greater storage capacity.

Storage Concepts
In February of this year, Storage Concepts (Irvine, CA) announced that they had broken the 100 MBps barrier with their C814 FibreRAID product. At this sustained rate, the product is capable of transferring video at 3x real-time or supporting three simultaneous uncompressed video streams. Other FibreRAID products offer sustained transfer rates of 40 MBps or 80 MBps using a Fibre Channel interface. The speed depends on the disks being used in the system - 4 GB disks achieve the slower rate and newer, 9 GB disk technology achieves the higher rate.

Multiple FibreRAID chassis can be used in an installation with a maximum capacity of 72 GB per chassis. Host adapters and software are available to allow FibreRAID to be used in PCs running Windows NT, SGI workstations with GIO/HIO bus designs and VME bus platforms supporting a number of operating systems.

For the past few years, FWB has been in attendance at NAB with their SledgeHammer systems. These systems are now marketed by StreamLogic Corporation (Menlo Park, CA) and the SledgeHammer family continues to grow. As of last year, this extensive product family includes the SledgeHammer Pro line of disk drives and disk arrays. These products are already shipping for PCs and Macs, with a recently announced SGI version scheduled to ship next month.

SledgeHammer Pro utilizes Ultra SCSI Differential technology for throughput of up to 60 MBps. SledgeHammer Pro disk arrays are available in 2, 4, and 8 bay configurations. They range in size from 4 GB up to 69 GB per system and can total over 540 GB when daisy-chained together.

Byte Off as Much as You Can Handle
The companies and products listed here offer a wide variety of capacities, interfaces and speeds for connecting digital storage to individual workstations or networks. In every case, the solutions described are designed to offer the throughput necessary to work with audio and video information. A few of these products have been around for a year or more, others have just been introduced and some only qualify as technology demonstrations at this point. But, if you can see them work on the machine and/or with the software you use, you should be able to use any of them. So don't be afraid to take a big bite - you can never have too much storage.

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