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US Doubler Usage

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I decided to open my 1050 that I received not to long ago to do some maintenance before I put the drive to good use.

 

Upon removal of the drive I found an ICD doubler. This consists of a masked ROM and the special RAM that has ICD in it.

 

The instruction mention a Special version of SpartaDOS?

 

So how to I test the doubler to make sure its working?

 

It does offer true double density?

 

Thanks in advance !!

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US Doubler offers two things with the minimal of additional hardware (replacement ROM, and 256 bytes of sector buffer instead of 128)

  • True double density support
  • Ultraspeed SIO rate (54000bps instead of 19200)

No track buffer, so when using a handler or DOS that enables ultraspeed mode (ie SpartaDOS) you need to format them with an alternate sector interleave aka skew to achieve the fastest throughput. The format tools in disk and cartridge based spartaDOS have an option to select standard or ultraspeed when formatting.

 

A good test is to boot up with SpartaDOS, and format a new disk with your choice of double density and/or ultraspeed interleave.

 

Here is the manual: https://archive.org/details/icd-us-doubler-manual

Some disk-based ATR images of SpartaDOS are here: https://seriouscomputerist.atariverse.com/pages/dos/dos.sparta.htm

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1 minute ago, Nezgar said:

 

A good test is to boot up with SpartaDOS, and format a new disk with your choice of double density and/or ultraspeed interleave.

 

Thanks Nezgar!

 

I went digging and found my Spartados X cart and found in the manual and Format with Skew for high speed and density for double density.

 

Now I can test the ICD chip!

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I have looked at the rom code. 1st thing it does is test for the special ram module. If drive appears to turn on like a 1050, then it should be OK. assuming no other lurking problems elsewhere.

 

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