Subject: Ram Disk card

From: "jacques" <[email-masked]>
Date: Fri, 12 Aug 2011 13:08:35 -0300

I recently found that I have a Ram Disk card that shows up as having 768
sectors. This is not a HRD card but indicates that it was built by Midwest
Engineering Consultants copyright 1988. I was able to load ROS into this
card and I created a 720 sector disk. The card would hold its contents while
power to the TI was on, but lost it when I turned off the console. The three
batteries placed across the top of the card are obviously corroded. These
batteries are rechargeable nickel-cadmium AA Panasonic and show P-50AA
(NR-AA) 1.2V 500mAh along the side. I was going to try and replace the
batteries myself but because my soldering skills are not as good as when I
was younger I am going to get a local computer shop do the work. They did
similar work for me on a HRD card a few years ago.

What replacement batteries should be used?

Also, the card has six RCA Z CDM62256E10 814 chips and there are five
adjacent free sockets of the same size. If my math is correct this is 6 32K
memory chips for 192 sectors and I could add 5 32K chips for an additional
160 sectors. I think that I may be confusing disk size with sectors but you
probably know what I mean. <grin> Are these common chips that are easy to
get?

Since I have one remaining slot in my PEB I feel that I might as well fill 
it.

Regards,

Jacques

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From: "epergrem" <[email-masked]>
Date: Fri, 12 Aug 2011 17:07:40 -0000

The Midwest Engineering card was created by George Bowman, who was a CTIUG member. It was sold by Bud Mills Services for a while, but the partnership dissolved. Without modification, when fully populated, it was a 384K card.  You can use the same 32K SRAM chips that are in the Horizon card if you have spares.

There should be some docs for it on the WHT FTP site.

Ernie

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From: Insane Multitasker <[email-masked]>
Date: Sun, 14 Aug 2011 21:44:14 -0500

Jacques,
 
To arrive at your currently available sector count (768) you
would multiply the number of RAM chips (6) * size of the 
chip (32K) * sectors per K (4): 
 
6 chips * 32K * 4sectors/K = 768 sectors
 
If you populate the remaining sockets:
 
5 chips * 32K * 4sectors/K = 640 sectors
 
768+640 = 1408 sectors maximum possible sectors
 
I have one of these same RAMdisks but it is populated with stacked
8K chips. 
 
Tim

> To: [email-masked]
> From: [email-masked]
> Date: Fri, 12 Aug 2011 13:08:35 -0300
> Subject: [TI994A] Ram Disk card
> 
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