Double Density Board
Add 80% more capacity to your disk system with the Double Density Controller (DDC) from Aerocomp.
The Story
Some products have what it takes to seem to last forever. Our DDC" is one of those products. What it does is allow you to operate your TRS-80 Model 1 disk system m double density In this case double density means almost doubling the storage capacity of your diskettes Single density, thats the way Radio Shack designed your Model I expansion interlace, organizes your disk into 10 sectors per track. Each sector contains 256 bytes of data for a total storage capacity of 2,560 bytes or 2.5K per track times the number of tracks your dnve is capable of adressing. Double density, on the other hand, wntes 18 sectors per track each containing 256 bytes for a total of 4.608 bytes or 4.5K That is 80% more data in the same space Why didn't Radio Shack do that in the beginning, you ask? Well it costs money to do double density because it is more difficult to do than single density and the data is harder to capture reliably. That means more cost and the Model I was meant to be a low-cost computer for the masses Therefore, no double density for the onginal Model I
The Facts
Other companies introduced double density controllers for the Model I but they were not so good. We waited and waited but, even new models failed to correct problems with data separation that kept cropping up. So we went to work and came up with a new design to cure the old problem. At last! A double density controller for the Model I with a higher probability of data recovery than with any other double density controller on the market then or since Our analog design phase lock loop data separator has a wider capture window than the digital types the others use This allows high resolution data centering. Our "DDC" analog circuit allows infinately variable tuning The attack and settling times are optimum tor 5.25" diskettes The oft-stated fears of adjustment problems rumored by digital dilettantes have been proved groundless by thousands of satisfied users the world over The bottom line here is state-of-the-art performance and reliability
See opposite page
- Copyrtghl 1965
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