What Good is a zEDC Card?

BrettBy Dave Heggen

informatics inc: You Need Our Shrink!

The technologies involving compression have been looking for a home on z/OS for many years. There have been numerous implementations to perform compression, all with the desired goal of reducing the number of bits needed to store or transmit data. Hostbased implementations ultimately trade MIPS for MB. Outboard hardware implementations avoid this issue.

Examples of Compression Implementations

The first commercial product I remember was from Informatics, named Shrink, sold in the late 1970s and early 1980s. It used host cycles to perform compression, could generally get about a 2:1 reduction in file size and, in the case of the IMS product, worked through exits so programs didn’t require modification. Sharing data compressed in this manner required accessing the data with the same software that compressed the data to expand it.

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Mainframe Capacity “Through the Looking Glass”


By Todd Havekost


With the recent release of “Alice Through the Looking Glass” (my wife is a huge Johnny Depp fan), it seems only appropriate to write on a subject epitomized by Alice’s famous words:

“What if I should fall right through the center of the earth … oh, and come out the other side, where people walk upside down?”  (Lewis Carroll, Alice in Wonderland)

Along with the vast majority of the mainframe community, I had long embraced the perspective that running mainframes at high levels of utilization was essential to operating in the most cost-effective manner. Based on carefully constructed capacity forecasts, our established process involved implementing just-in-time upgrades designed to ensure peak utilization’s remained slightly below 90%.

It turns out we’ve all been wrong.  Continue reading