Posted By
JamesD
on 2016-09-18
18:28:36
|  Re: What would I do differently in the Plus/4
Good points.
As you say, Commodore did have higher capacity devices off of the IEE-488 buss.
But you are talking about another connector, a controller chip, and the Kernel either has to support two interfaces, or it has to drop the cheaper one in favor of more expensive devices only.
Dropping the cheaper interface makes no sense, since that is required by the 116 and for compatibility.
I don't think that an integrated controller chip existed, so that would have to be developed.
Adding it to the TED would be a violation of the prime directive of this topic and I don't see it as feasible cost wise anyway.
A controller chip and large connector will add to the price of the machine, it might impact FCC testing, and the data storage devices seem a little expensive for the price of the computer.
If the controller chip didn't exist, development would have had to start after Jack was booted, after all, the idea of pitching the TED in a business system came after that.
So you have a short time frame for developing the chip which would be a risk.
Adding the IEEE connector would require dropping an expansion port, or a wider motherboard.
If you have a wider motherboard, you need a wider machine and Commodore may as well add the numeric keypad.
We aren't talking about just adding a header to the motherboard for a RAM expansion, a kernel change, and some changes to BASIC like I was. This is a significant hardware change and price change.
I think adding $5-$10 to the cost of the Plus/4 is one thing, but how much would other changes add to the price?
Commodore tried many more expensive business systems and they are all very rare.
You are correct in that the 1571 did not exist when the Plus/4 came out.
I'm suggesting moving that project ahead instead of the 1551 parallel drive. It probably would have cost a little more at that time than when it was actually released though.
The 1551 parallel drive should be faster than the 1571, and if it had been double sided that might have been an even better option than the 1571. But you end up with a product that can only work on the Plus/4 and not older machines.
I think the 1571 looks better to consumers buying a drive for an existing machine who plan to upgrade the computer in the future, if it's fully compatible with old software.
If Commodore drops the 1541 for only one product, I think the 1571 makes the most sense and they get away from the 1541 heat issues.
Retailers could stock one product instead of several with the 1571.
So the 1571 is probably a good option for everything but speed.
Atari didn't catch the same flack that Commodore did for slow drives and it uses a serial interface, so the potential is there. The question becomes is the burst mode fast enough?
I found conflicting numbers for the transfer rate so I really can't say.
The 1551 can supposedly transfer 1K per second according to one page and the 1571 can transfer 3K per second according to another. ???????
I can say this, if you are loading 16K programs, it's going to seem very fast. If you are loading 128K all at once... it's going to take over 40 seconds even at 3K per second. At least it's not cassette slow.
I think some of that 128K expansion could be a RAM disk. If the changes to make BASIC support RAM expansions are too complex, that's the fallback option from BASIC anyway.
|
