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Conquer Your Fear of Corrupted Files with TANDsoft’s Block Technology



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Woe is the victim of the dreaded Error 59. You attempt to open a file to read or write a record only to be denied access. Staring back at you from your screen are the terrible words, “An unexpected error has occurred.” Scared?  You should be. The disk file may be bad, there may be a mismatch in the internal File Control Block, or the file structure in a structured file may be inconsistent.  If a file is large with multiple partitions, but only one partition is corrupt, too bad. The entire file is considered broken. Access denied.

A file that has been corrupted may take hours to rebuild and additional hours to synchronize.  Even if only a part of the file has been corrupted, record mode requires a whole file rebuild, a record at a time. The corrupted elements cannot be repaired at the record level. You start from zero. In the meantime, applications that must access the file cannot proceed.

Block technology, on the other hand, compares source and target files via chunks of a file, or blocks. It is not cognizant of the need for sequential order or internal structure.  Block technology compares source and target hash block signatures to determine if the corresponding blocks are equal.

If, for instance, there are 1,000 blocks, but only Blocks #5 and #537 are out-of-sync between the source and target databases, block technology allows a user to open a file that has been deemed corrupted, identify the blocks that are broken, repair them, and resynchronize newly repaired blocks with the source database. Instead of whole file rebuild, you have block resynchronization. Hours to fix are reduced to seconds. Fast.

Three TANDsoft software solutions are based on block technology.  They repair all file types, work with all HPE NonStop replication vendors, and require only seconds to repair a corrupted file, not hours.

FileSync automatically monitors, replicates and synchronizes application environments and non-database files (edit, objects, source, TACL, blobs, OSS, SQL/MP, SQL/MX) across HPE NonStop servers. It reduces the errors associated with maintaining duplicate system and application environments. Use FileSync for system migrations, upgrades, and backups. Its affordability and ease-of-use complement other NonStop third-party data replication products for a complete business continuity solution. For large, unaudited files, FileSync Data Deduplication transmits only changed data blocks, not entire files, to synchronize a backup database.

FS Compare and Repair identifies, reports, and resolves rows, records, columns and field inconsistencies in both live and offline databases. Block Hash Compare technology is what makes this solution blazing fast. In addition, FS Compare and Repair efficiently performs multiple partition and index comparisons in parallel rather than sequentially. Between block-level comparisons, Block Hash Compare, and parallel processing capabilities, FS Compare and Repair is the fastest solution of its kind for use in the HPE NonStop environment.

Backup times that formerly may take hours can be reduced to minutes with FS Backup and Restore. Rather than archive whole files to disk, tape or virtual tape, FS Backup detects file data-block modifications and archives only the changes. FS Restore then retrieves the saved file data-block modifications and will apply the changes to rebuild the original file. FS Backup and Restore complements the HPE NonStop Backup and Restore utilities as well as all third-party storage solutions.

As is the case with so many partner software products, it was a customer comment about an internal database issue that brought to TANDsoft the realization of the value of its block technology in general and block hash compare specifically. As today’s files grow from large to immense to even mammoth, the solutions that are sought offer repair and recovery at the fastest speeds and timeframes possible. Anything to avoid the dreaded appearance of Error 59.


Contact Jack Di Giacomo (+1 514-695-2234 /

or Dieter Orlowski (+1 303-263-4381 /

TANDsoft is a global provider of innovative HPE NonStop software solutions for use in time virtualization, application modernization, security, and business continuity. Our intercept technology is used by many NonStop customers to enhance application functionality with no program modifications. Our products are easy to install, easy to use, and are certified on all HPE NonStop servers. Check us out at