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Banking Special Issue: Thrashing

Table of Contents


The Future of Bank Imaging

The green wall

Relationship Banking

Proof of Deposit

POD Case Study

Designing Forms for a Banking Environment

File Folders

Thrashing Folders

Staging Folders

Using COLD (a case study)

Check Processing: The need for Speed

Printing Your Own Checks

Check Processing 101

Images from the Fed

First National Bank & the Fed (case study)

Glossary of Bank Image Technology


by Joe Devlin

Banking on Folders Part 2

Problems can arise when banks begin to integrate information, such as check images, captured signature cards and loan information, into file folders. This is especially true when new images are frequently scanned or shipped into the system. File clerks may think they are asking for related files, whereas the system sees someone trying to access unrelated, randomly distributed files.

This phenomenon is called "Thrashing," referring to the constant mounting and dismounting of platters that occurs when a system is looking for a customer's images that have been written to different disks. For example, if you stored a customer's credit application on disk #1, his signature card on disk #2, and his credit report on disk #3, and you tried to print his entire folder, the system would have to mount and dismount each of these platters to find the images. "When this happens, the effect can be felt by everyone using the system," warns Tom Houston, president of Cabbage Mountain Image Consultants of Atlanta, GA.

In theory, the solution to this problem is simple - keep all of a customer's images on a single disk. Most banks these days use different devices for storing and backing up data, typically optical or magnetic disk for primary storage and tape for backup.

This provides an easy way to consolidate files - simply stream all the related customer files off to tape late at night and then copy them back to the primary storage when all the related files have been placed together. In essence, you are performing exactly the same sort of operation you do when you run a Norton speed disk on your local hard drive.

Of course it is never as simple as all that. "Image management is always more controversial than politics," warns Houston. "Putting everything on one disk takes up more optical disk storage space than housing it separately would. Remember, maintaining folder integrity may require you to rewrite entire folders whenever updates occur. A loan folder may grow to 2 to 3 megabytes and replicating it with each update gives cause for storage concerns if you have a large, active loan portfolio. This may seem like a reseller's dream sales situation - an instance where selling the customer more equipment can help overcome a clearly perceived problem, but you must also face the reality that customers are usually skeptical of any sales approach that says you have to buy more from me to fix this problem and the politics of reworking the storage architecture of imaging systems you may or may not have sold in the first place."

In a real-world situation, it is invariably too expensive to keep every record for a customer together, on the same spot, on the same disk. "On average, 90 percent of all check research items occur within 90 days of processing," Houston says. "This means that keeping three or four months worth of checks on the primary disk along with frequently accessed document images of other types can reduce thrashing down to bare minimum. Old check images and other Infrequently accessed documents can be stored back to less expensive, slower access methods controlled by the Hierarchical Storage Management (HSM) System." 

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