Tony Pearson is a Master Inventor and Senior IT Architect for the IBM Storage product line at the
IBM Systems Client Experience Center in Tucson Arizona, and featured contributor
to IBM's developerWorks. In 2016, Tony celebrates his 30th year anniversary with IBM Storage. He is
author of the Inside System Storage series of books. This blog is for the open exchange of ideas relating to storage and storage networking hardware, software and services.
(Short URL for this blog: ibm.co/Pearson )
My books are available on Lulu.com! Order your copies today!
Safe Harbor Statement: The information on IBM products is intended to outline IBM's general product direction and it should not be relied on in making a purchasing decision. The information on the new products is for informational purposes only and may not be incorporated into any contract. The information on IBM products is not a commitment, promise, or legal obligation to deliver any material, code, or functionality. The development, release, and timing of any features or functionality described for IBM products remains at IBM's sole discretion.
Tony Pearson is a an active participant in local, regional, and industry-specific interests, and does not receive any special payments to mention them on this blog.
Tony Pearson receives part of the revenue proceeds from sales of books he has authored listed in the side panel.
Tony Pearson is not a medical doctor, and this blog does not reference any IBM product or service that is intended for use in the diagnosis, treatment, cure, prevention or monitoring of a disease or medical condition, unless otherwise specified on individual posts.
Wrapping up my week's theme of storage optimization, I thought I would help clarify the confusion between data reduction and storage efficiency. I have seen many articles and blog posts that either use these two terms interchangeably, as if they were synonyms for each other, or as if one is merely a subset of the other.
Data Reduction is LOSSY
By "Lossy", I mean that reducing data is an irreversible process. Details are lost, but insight is gained. In his paper, [Data Reduction Techniques", Rajana Agarwal defines this simply:
"Data reduction techniques are applied where the goal is to aggregate or amalgamate the information contained in large data sets into manageable (smaller) information nuggets."
Data reduction has been around since the 18th century.
Take for example this histogram from [SearchSoftwareQuality.com]. We have reduced ninety individual student scores, and reduced them down to just five numbers, the counts in each range. This can provide for easier comprehension and comparison with other distributions.
The process is lossy. I cannot determine or re-create an individual student's score from these five histogram values.
This next example, complements of [Michael Hardy], represents another form of data reduction known as ["linear regression analysis"]. The idea is to take a large set of data points between two variables, the x axis along the horizontal and the y axis along the vertical, and find the best line that fits. Thus the data is reduced from many points to just two, slope(a) and intercept(b), resulting in an equation of y=ax+b.
The process is lossy. I cannot determine or re-create any original data point from this slope and intercept equation.
In this last example, from [Yahoo Finance], reduces millions of stock trades to a single point per day, typically closing price, to show the overall growth trend over the course of the past year.
The process is lossy. Even if I knew the low, high and closing price of a particular stock on a particular day, I would not be able to determine or re-create the actual price paid for individual trades that occurred.
Storage Efficiency is LOSSLESS
By contrast, there are many IT methods that can be used to store data in ways that are more efficient, without losing any of the fine detail. Here are some examples:
Thin Provisioning: Instead of storing 30GB of data on 100GB of disk capacity, you store it on 30GB of capacity. All of the data is still there, just none of the wasteful empty space.
Space-efficient Copy: Instead of copying every block of data from source to destination, you copy over only those blocks that have changed since the copy began. The blocks not copied are still available on the source volume, so there is no need to duplicate this data.
Archiving and Space Management: Data can be moved out of production databases and stored elsewhere on disk or tape. Enough XML metadata is carried along so that there is no loss in the fine detail of what each row and column represent.
Data Deduplication: The idea is simple. Find large chunks of data that contain the same exact information as an existing chunk already stored, and merely set a pointer to avoid storing the duplicate copy. This can be done in-line as data is written, or as a post-process task when things are otherwise slow and idle.
When data deduplication first came out, some lawyers were concerned that this was a "lossy" approach, that somehow documents were coming back without some of their original contents. How else can you explain storing 25PB of data on only 1PB of disk?
(In some countries, companies must retain data in their original file formats, as there is concern that converting business documents to PDF or HTML would lose some critical "metadata" information such as modificatoin dates, authorship information, underlying formulae, and so on.)
Well, the concern applies only to those data deduplication methods that calculate a hash code or fingerprint, such as EMC Centera or EMC Data Domain. If the hash code of new incoming data matches the hash code of existing data, then the new data is discarded and assumed to be identical. This is rare, and I have only read of a few occurrences of unique data being discarded in the past five years. To ensure full integrity, IBM ProtecTIER data deduplication solution and IBM N series disk systems chose instead to do full byte-for-byte comparisons.
Compression: There are both lossy and lossless compression techniques. The lossless Lempel-Ziv algorithm is the basis for LTO-DC algorithm used in IBM's Linear Tape Open [LTO] tape drives, the Streaming Lossless Data Compression (SLDC) algorithm used in IBM's [Enterprise-class TS1130] tape drives, and the Adaptive Lossless Data Compression (ALDC) used by the IBM Information Archive for its disk pool collections.
Last month, IBM announced that it was [acquiring Storwize. It's Random Access Compression Engine (RACE) is also a lossless compression algorithm based on Lempel-Ziv. As servers write files, Storwize compresses those files and passes them on to the destination NAS device. When files are read back, Storwize retrieves and decompresses the data back to its original form.
As with tape, the savings from compression can vary, typically from 20 to 80 percent. In other words, 10TB of primary data could take up from 2TB to 8TB of physical space. To estimate what savings you might achieve for your mix of data types, try out the free [Storwize Predictive Modeling Tool].
So why am I making a distinction on terminology here?
Data reduction is already a well-known concept among specific industries, like High-Performance Computing (HPC) and Business Analytics. IBM has the largest marketshare in supercomputers that do data reduction for all kinds of use cases, for scientific research, weather prediction, financial projections, and decision support systems. IBM has also recently acquired a lot of companies related to Business Analytics, such as Cognos, SPSS, CoreMetrics and Unica Corp. These use data reduction on large amounts of business and marketing data to help drive new sources of revenues, provide insight for new products and services, create more focused advertising campaigns, and help understand the marketplace better.
There are certainly enough methods of reducing the quantity of storage capacity consumed, like thin provisioning, data deduplication and compression, to warrant an "umbrella term" that refers to all of them generically. I would prefer we do not "overload" the existing phrase "data reduction" but rather come up with a new phrase, such as "storage efficiency" or "capacity optimization" to refer to this category of features.
IBM is certainly quite involved in both data reduction as well as storage efficiency. If any of my readers can suggest a better phrase, please comment below.
This week, I am in beautiful Sao Paulo, Brazil, teaching Top Gun class to IBM Business Partners and sales reps. Traditionally, we have "Tape Thursday" where we focus on our tape systems, from tape drives, to physical and virtual tape libraries. IBM is the number #1 tape vendor, and has been for the past eight years.
(The alliteration doesn't translate well here in Brazil. The Portuguese word for tape is "fita", and Thursday here is "quinta-feira", but "fita-quinta-feira" just doesn't have the same ring to it.)
In the class, we discussed how to handle common misperceptions and myths about tape. Here are a few examples:
Myth 1: Tape processing is manually intensive
In my July 2007 blog post [Times a Million], I coined the phrase "Laptop Mentality" to describe the problem most people have dealing with data center decisions. Many folks extend linearly their experiences using their PCs, workstations or laptops to apply to the data center, unable to comprehend large numbers or solutions that take advantage of the economies of scale.
For many, the only experience dealing with tape was manual. In the 1980s, we made "mix tapes" on little cassettes, and in the 1990s we recorded our favorite television shows on VHS tapes in the VCR. Today, we have playlists on flash or disk-based music players, and record TV shows on disk-based video recorders like Tivo. The conclusion is that tapes are manual, and disk are not.
Manual processing of tapes ended in 1987, with the introduction of a silo-like tape library from StorageTek. IBM quickly responded with its own IBM 3495 Tape Library Data Server in 1992. Today, clients have many tape automation choices, from the smallest IBM TS2900 Tape Autoloader that has one drive and nine cartridges, all the way to the largest IBM TS3500 multiple-library shuttle complex that can hold exabytes of data. These tape automation systems eliminate most of the manual handling of cartridges in day-to-day operations.
Myth 2: Tape media is less reliable than disk media
For any storage media to be unreliable is to return the wrong information that is different than what was originally stored. There are only two ways for this to happen: if you write a "zero" but read back a "one", or write a "one" and read a "zero". This is called a bit error. Every storage media has a "bit error rate" that is the average likelihood for some large amount of data written.
According to the latest [LTO Bit Error rates, 2012 March], today's tape expects only 1 bit error per 10E17 bits written (about 100 Petabytes). This is 10 times more reliable than Enterprise SAS disk (1 bit per 10E16), and 100 times more reliable than Enterprise-class SATA disk (1 bit per 10E15).
Tape is the media used in "black boxes" for airplanes. When an airplane crashes, the black box is retrieved and used to investigate the causes of the crash. In 1986, the Space Shuttle Challenger exploded 73 seconds after take-off. The tapes in the black box sat on the ocean floor for six weeks before being recovered. Amazingly, IBM was able to successfully restore [90 percent of the block data, and 100 percent of voice data].
Analysts are quite upset when they are quoted out of context, but in this case, Gartner never said anything closely similar to this. Nor did the other analysts that Curtis investigated for similar claims. What Garnter did say was that disk provides an attractive alternative storage media for backup which can increase the performance of the recovery process.
Back in the 1990s, Savur Rao and I developed a patent to help backup DB2 for z/OS by using the FlashCopy feature of IBM's high-end disk system. The software method to coordinate the FlashCopy snapshots with the database application and maintain multiple versions was implemented in the DFSMShsm component of DFSMS. A few years later, this was part of a set of patents IBM cross-licensed to Microsoft for them to implement a similar software for Windows called Data Protection Manager (DPM). IBM has since introduced its own version for distributed systems called IBM Tivoli FlashCopy Manager that runs not just on Windows, but also AIX, Linux, HP-UX and Solaris operating systems.
Curtis suspects the "71 percent" citation may have been propogated by an ambitious product manager of Microsoft's Data Protection Manager, back in 2006, perhaps to help drive up business to their new disk-based backup product. Certainly, Microsoft was not the only vendor to disparage tape in this manner.
A few years ago, an [EMC failure brought down the State of Virginia] due to not just a component failure it its production disk system, but then made it worse by failing to recover from the disk-based remote mirror copy. Fortunately, the data was able to be restored from tape over the next four days. If you wonder why nobody at EMC says "Tape is Dead" anymore, perhaps it is because tape saved their butts that week.
(FTC Disclosure: I work for IBM and this post can be considered a paid, celebrity endorsement for all of the IBM tape and software products mentioned on this post. I own shares of stock in both IBM and Google, and use Google's Gmail for my personal email, as well as many other Google services. While IBM, Google and Microsoft can be considered competitors to each other in some areas, IBM has working relationships with both companies on various projects. References in this post to other companies like EMC are merely to provide illustrative examples only, based on publicly available information. IBM is part of the Linear Tape Open (LTO) consortium.)
Myth 4: Vendors and Manufacturers are no longer investing in tape technology
IBM and others are still investing Research and Development (R&D) dollars to improve tape technology. What people don't realize is that much of the R&D spent on magnetic media can be applied across both disk and tape, such as IBM's development of the Giant Magnetoresistance read/write head, or [GMR] for short.
Most recently, IBM made another major advancement with tape with the introduction of the Linear Tape File Systems (LTFS). This allows greater portability to share data between users, and between companies, but treating tape cartridges much like USB memory sticks or pen drives. You can read more in my post [IBM and Fox win an Emmy for LTFS technology]!
Next month, IBM celebrates the 60th anniversary for tape. It is good to see that tape continues to be a vibrant part of the IT industry, and to IBM's storage business!
Well, it's Tuesday again, and you know what that means! IBM Announcements!
Today, IBM announced its latest IBM Tivoli Key Lifecycle Manager (TKLM) 2.0 version. Here's a quick recap:
Centralized Key Management
Centralized and simplified encryption key management through Tivoli Key Lifecycle Manager's lifecycle of creation, storage, rotation, and protection of encryption keys and key serving through industry standards. TKLM is available to manage the encryption keys for LTO-4, LTO-5, TS1120 and TS1130 tape drives enabled for encryption, as well as DS8000 and DS5000 disk systems using Full Disk Encryption (FDE) disk drives.
Partitioning of Access Control for Multitenancy
Access control and partitioning of the key serving functions, including end-to-end authentication of encryption clients and security of exchange of encryption keys, such that groups of devices have different sets of encryption keys with different administrators. This enables [multitenancy] or multilayer security of a shared infrastructure using encryption as an enforcement mechanism for access control. As Information Technology shifts from on-premises to the cloud, multitenancy will become growingly more important.
Support for KMIP 1.0 Standard
Support for the new key management standard, Key Management Interoperability Protocol (KMIP), released through the Organization for the Advancement of Structured Information Standards [OASIS]. This new standard enables encryption key management for a wide variety of devices and endpoints. See the
[22-page KMIP whitepaper] for more information.
As much as I like to poke fun at Oracle, with hundreds of their Sun/StorageTek clients switching over to IBM tape solutions every quarter, I have to give them kudos for working cooperatively with IBM to come up with this KMIP standard that we can both support.
Support for non-IBM devices from Emulex, Brocade and LSI
Support for IBM self-encrypting storage offerings as well as suppliers of IT components which support KMIP, including a number of supported non-IBM devices announced by business partners such as Emulex, Brocade, and LSI. KMIP support permits you to deploy Tivoli Key Lifecycle Manager without having to worry about being locked into a proprietary key management solution. If you are a client with multiple "Encryption Key Management" software packages, now is a good time to consolidate onto IBM TKLM.
Role-based access control for administrators that allows multiple administrators with different roles and permissions to be defined, helping increase the security of sensitive key management operations and better separation of duties. For example, that new-hire college kid might get a read-only authorization level, so that he can generate reports, and pack the right tapes into cardboard boxes. Meanwhile, for that storage admin who has been running the tape operations for the past ten years, she might get full access. The advantage of role-based authorization is that for large organizations, you can assign people to their appropriate roles, and you can designate primary and secondary roles in case one has to provide backup while the other is out of town, for example.
In my presentations in Australia and New Zealand, I mentioned that people were re-discovering the benefits of removable media. While floppy diskettes were convenient way of passing information from one person to another, they unfortunately did not have enough capacity. In today's world, you may need Gigabytes or Terabytes of re-writeable storage with a file system interface that can easily be passed from one person to another. In this post, I explore three options.
(FCC Disclaimer: I work for IBM, and IBM has no business relationship with Cirago at the time of this writing. Cirago has not paid me to mention their product, but instead provided me a free loaner that I promised to return to them after my evaluation is completed. This post should not be considered an endorsement for Cirago's products. List prices for Cirago and IBM products were determined from publicly available sources for the United States, and may vary in different countries. The views expressed herein may not necessarily reflect the views and opinions of either IBM or Cirago.)
I took a few photos so you can see what exactly this device looks like. Basically, it is a plastic box that holds a single naked disk drive. It has four little rubber feet so that it does not slip on your desk surface.
The inside is quite simple. The power and SATA connections match those of either a standard 3.5 inch drive, or the smaller form factor (SFF) 2.5 inch drive. However, to my dismay, it does not handle EIDE drives which I have a ton of. After taking apart six different computer systems, I found only one had SATA drives for me to try this unit out with.
The unit comes with a USB cable and AC/DC power adapter. In my case, I found the USB 3.0 cable too short for my liking. My tower systems are under my desk, but I like keeping docking stations like this on the top of the desk, within easy reach, but that wasn't going to happen because the USB cable was not long enough.
Instead, I ended up putting it half-way in between, behind my desk, sitting on another spare system. Not ideal, but in theory there are USB-extension cables that probably could fix this.
Here it is with the drive inside. I had a 3.5 inch Western Digital [1600AAJS drive] 160 GB, SATA 3 Gbps, 8 MB Cache, 7200 RPM.
To compare the performance, I used a dual-core AMD [Athlon X2] system that I had built for my 2008 [One Laptop Per Child] project. To compare the performance, I ran with the drive externally in the Cirago docking station, then ran the same tests with the same drive internally on the native SATA controller. Although the Cirago documentation indicated that Windows was required, I used Ubuntu Linux 10.04 LTS just fine, using the flexible I/O [fio] benchmarking tool against an ext3 file system.
Sequential Write - a common use for external disk drive is backup.
Random read - randomly read files ranging from 5KB to 10MB in size.
Random mixed - randomly read/write files (50/50 mix) ranging from 5KB to 10MB in size.
Random Mixed (50/50)
Latency (msec) read
Latency (msec) write
Bandwidth (KB/s) read
Bandwidth (KB/s) write
For sequential write, the Cirago performed well, only about 15 percent slower than native SATA. For random workloads, however, it was 30-40 percent slower. If you are wondering why I did not get USB 3.0 speeds, there are several factors involved here. First, with overheads, 5 Gbps USB 3.0 is expected to get only about 400 MB/sec. My SATA 2.0 controller maxes out at 375 MB/sec, and my USB 2.0 ports on my system are rated for 57 MB/sec, but with overheads will only get 20-25 MB/sec. Most spinning drives only get 75 to 110 MB/sec. Even solid-state drives top out at 250 MB/sec for sustained activity. Despite all that, my internal SATA drive only got 16 MB/sec, and externally with the Cirago 14 MB/sec in sustained write activity.
Here is the mess that is inside my system. The slot for drive 2 was blocked by cables, memory chips and the heat sink for my processor. It is possible to damage a system just trying to squeeze between these obstacles.
However, the point of this post is "removable media". Having to open up the case and insert the second drive and wire it up to the correct SATA port was a pain, and certainly a more difficult challenge than the average PC user wishes to tackle.
Price-wise, the Cirago lists for $49 USD, and the 160GB drive I used lists for $69, so the combination $118 is about what you would pay for a fully integrated external USB drive. However, if you had lots of loose drives, then this could be more convenient and start to save you some money.
IBM RDX disk backup system
Another problem with the Cirago approach is that the disk drives are naked, with printed circuit board (PCB) exposed. When not in the docking station, where do you put your drive? Did you keep the [anti-static ESD bag] that it came in when you bought it? And once inside the bag, now what? Do you want to just stack it up in a pile with your other pieces of equipment?
To solve this, IBM offers the RDX backup system. These are fully compatible with other RDX sytems from Dell, HP, Imation, NEC, Quantum, and Tandberg Data. The concept is to have a docking station that takes removable, rugged plastic-coated disk-enclosed cartridges. The docking station can be part of the PC itself, similar to how CD/DVD drives are installed, or as a stand-alone USB 2.0 system, capable of processing data up to 25 MB/sec.
The idea is not new, about 10 years ago we had [Iomega "zip" drives] that offered disk-enclosed cartridges with capacities of 100, 250 and 750MB in size. Iomega had its fair share of problems with the zip drive, which were ranked in 2006 as the 15th worst technology product of all time, and were eventually were bought out by EMC two years later (as if EMC has not had enough failures on its own!)
The problem with zip drives was that they did not hold as much as CD or DVD media, and were more expensive. By comparison, IBM RDX cartridges come in 160GB to 750GB in size, at list prices starting at $127 USD.
IBM LTO tape with Long-Term File System
Removable media is not just for backup. Disk cartridges, like the IBM RDX above, had the advantage of being random access, but most tape are accessed sequentially. IBM has solved this also, with the new IBM Long Term File System [LTFS], available for LTO-5 tape cartridges.
With LFTS, the LTO-5 tape cartridge now can act as a super-large USB memory stick for passing information from one person to the next. The LTO-5 cartridge can handle up to 3TB of compressed data at up to SAS speeds of 140 MB/sec. An LTO-5 tape cartridge lists for only $87 USD.
The LTO-5 drives, such as the IBM [TS2250 drive] can read LTO-3, LTO-4 and LTO-5cartridges, and can write LTO-4 and LTO-5 cartridges, in a manner that is fully compatible with LTO drives from HP or Quantum. LTO-3, LTO-4 and LTO-5 cartridges are available in WORM or rewriteable formats. LTO-4 and LTO-5 cartridges can be encrypted with 256-bit AES built-in encryption. With three drive manufacturers, and seven cartridge manufacturers, there is no threat of vendor lock-in with this approach.
These three options offer various trade-offs in price, performance, security and convenience. Not surprisingly, tape continues to be the cheapest option.
This year marks the 10 year anniversary of IBM's introduction of LTO tape technology. IBM is a member of the Linear Tape Open consortium which consists of IBM, HP and Quantum, referred to as "Technology Provider Companies" or TPCs. In an earlier job role, I was the "portfolio manager" for both LTO and Enterprise tape product lines.
Today, we held a celebration in Tucson, with cake and refreshments.
IBM Executives Doug Balog, IBM VP of Storage Platform, and Sanjay Tripathi, the new IBM Director and Business Line Executive for Tape, VTL and Archive systems, presented the successes of LTO tape over the past 10 years.
To date over 3.5 million LTO tape drives, and over 150 million LTO tape media cartridges have been shipped which is a testament to the remarkable marketplace acceptance of the technology.
In honor of this event, I decided to interview Bruce Master, IBM Senior Program Manager for Data Protection Systems, about this 10 year anniversary.
10 years of LTO technology is a great milestone. How is this especially significant to IBM and its clients?
According to IDC data, IBM has held the #1 leader position in market share for total world wide branded tape revenue for over 7 years and that IBM is still #1 in branded midrange tape revenue which includes the LTO tape technologies. IBM was the first drive manufacturer to deliver LTO-1 drives, back in September 2000, the first to deliver tape drive encryption to the marketplace on LTO-4 drives, and is shipping LTO generation 5 drives and libraries. IBM is the author of the new Linear Tape File System (LTFS) specification that has been adopted by the TPCs. This file system revolutionizes how tape can be used as if it were a giant 1.5 terabyte removable USB memory stick with the capability to be accessed with directory tree structures and drag and drop functionality. With LTO's built-in real-time compression, a single tape cartridge can hold up to 3TB of data.
The Linear Tape File System has been getting a lot of attention. Where can we learn more about it?
Why is tape still a critical part of a storage infrastructure?
Tape is low cost and provides critical off-line portable storage to help protect data from attacks that can occur with on-line data. For instance, on-line data is at risk of attack from a virus, hacker, system error, disgruntled employee, and more. Since tape is off-line, not accessible by the system, it protects against these forms of corruption. LTO technology also provides write-once read-many (WORM) tape media to help address compliance issues that specify non-erasable, non-rewriteable (NENR) storage, hardware encryption to secure data, as well as a low cost long term archive media. When data cools off, or becomes infrequently accessed, why keep it on spinning disk? Move it to tape where it is much greener and lower cost. A tape in a slot on a shelf consumes minimal energy.
So tape is not dead?
Ha! Far from it. Seems like disk-only "specialty shop" storage vendors that don’t have tape in their sales portfolio are the ones that propagate that myth. In reality, storage managers are tasked with meeting complex objectives for performance, compliance, security, data protection, archive and total cost of ownership. Optimally, a blend of disk and tape in a tiered infrastructure can best address these objectives. You can’t build a house with just a hammer. IBM has a rich tool kit of storage offerings including disk, tape, software, services and deduplication technologies to help clients address their needs.
Do you have an example of a client who was saved by tape?
Yes indeed. Estes Express, a large trucking firm, was hit by a hurricane that flooded their data center and destroyed all systems. Fortunately the company survived because the night before they had backed up all data on to IBM tape and moved the cartridges offsite! The company survived and has since implemented a best practices data protection strategy with a combination of disk-to-disk-to-tape (D2D2T) using LTO tape at the primary site, and a remote global mirrored site that is also backed up to LTO tape.
So tape saved the day. What is the outlook for tape innovation in the future?
The future is bright for tape. Earlier this year, IBM and Fujifilm were able to [demonstrate a tape density achievement] that could enable a native 35TB tape cartridge capacity! This shows a long roadmap ahead for tape and a continued good night’s sleep for storage managers knowing that their precious data will be safe.
Of course, LTO tape is just one of the many reasons IBM is a successful and profitable leader in the IT storage industry. Doug Balog talked about his experiences in London for the [October 7th launch] of IBM DS8800, Storwize V7000 and SAN Volume Controller 6.1. Sanjay Tripathi showed recent successes with IBM's ProtecTIER Data Deduplication Solution and Information Archive products.
I would like to thank Bruce Master for his time in completing this interview. To learn more about IBM tape and storage offerings, visit [ibm.com/storage].
IBM makes another breakthrough today with an announcement about tape data density. Unlike hard disk drive technologies that are hitting physical limits, IBM is proving that tape technology still has plenty of life in its future.
When I first started working for IBM in Tucson, back in 1986, a 3420 tape reel held only 180MB of data, and a 3480 tape cartridge improved this to 200MB of data. Today's enterprise tapes, like 3592 cartridges for the TS1130 drives, or LTO4 cartridges for the IBM TS1040 drives, are half-inch wide, half-mile long, and can store 1 TB or more of data per cartridge, depending on how well the data can compress. To increase cartridge capacity, designers can make changes in three dimensions:
Wider tape: The film industry tried this, going from 35mm to 70mm film, only to find that most cinemas did not want to upgrade their equipment. Keeping the media dimensions to half inch wide allows much of the engineering hardware to continue unchanged.
Longer tape: The problem with longer tape is that either the reel inside gets fatter, or you need to develop flatter media to fit within the existing cartridge dimensions. Wider reels means a bigger tape cartridge external dimensions, forcing changes to shelving units, cartridge trays, and carrying units. The media just can't get any flatter without risking getting more brittle.
Denser bit recording: once a convenient width and length were established, improving bit density turned out to be the best way to increase cartridge capacity.
Working with FujiFilm Corporation of Japan, my colleagues at IBM Research facility in Zurich were able to demonstrate an incredible 29.5 Gigabits per square inch, nearly 40 times more dense than today's commercial tape technology. In the near future, we will be able to hold a 35TB tape cartridge in our hand. There was actually a lot to make this happen, improved giant magentoresistive read/write heads, better servo patterns to stay on track, thinner tracks less than a micron thick, and better signal-to-noise processing to accomplish this. To learn more, you can read the [Press Release] or watch this quick [4-minute YouTube video].