HP-71B: Newbie Question

[smp]

Hello all,

Now that I have my HP-71B all up and running with pyILPER, I continue to explore for additional hardware. I currently have one 4K RAM module, one 32K RAM module (currently acting as a ROM), and the HP Forth/Assembler module, all plugged into my front ports (1, 2, & 4). Is it possible to plug in a second 32K RAM module into my front port 3?

Yes, I was on the list for a FRAM71, but circumstances were not right for me when they became available, so I didn't get one. I recently contacted Hans, but he said there are no more available. That's pretty much the normal story for me - never in sync with what's going on. Sigh.

Thanks very much, in advance, for your patience and assistance.

smp

[Dave Frederickson]

Yes, you can plug additional memory modules into any available port. That includes front-port modules up to 64k and Card Reader port modules up to 160k. In exotic configurations you can even plug a front-port module into the HP-IL port.

Weren't you on the list for a FRAM71? That's really the best way to go.

If all you need is an additional 32k module then send me a PM. I have several available.

Dave

[smp]

(06-17-2017 04:40 PM)Dave Frederickson Wrote:  Yes, you can plug additional memory modules into any available port. That includes front-port modules up to 64k and Card Reader port modules up to 160k. In exotic configurations you can even plug a front-port module into the HP-IL port.

Weren't you on the list for a FRAM71? That's really the best way to go.

If all you need is an additional 32k module then send me a PM. I have several available.

Dave

Hi Dave, and thanks very much for your quick response!

So, since I already have a 4k RAM module and a 32K RAM module, and you say I can have up to 64K RAM, what would happen if I add a second 32K RAM module? Sure, while the first 32K RAM module is acting as indirect storage, that would be OK, but what if I attempt to claim the first 32K RAM module back into main memory? This is what's confusing me. Would I have to pull the 4K RAM module out?

Yes, I was on the list for a FRAM71, but circumstances were not right for me when the time came, and I didn't get one. I recently contacted Hans, and he told me that they are long gone. Sigh. That's the way things often work for me - never in sync with what's going on.

Thanks very much for your patience!

smp

[Dave Frederickson]

(06-17-2017 05:12 PM)smp Wrote:  So, since I already have a 4k RAM module and a 32K RAM module, and you say I can have up to 64K RAM, what would happen if I add a second 32K RAM module? Sure, while the first 32K RAM module is acting as indirect storage, that would be OK, but what if I attempt to claim the first 32K RAM module back into main memory? This is what's confusing me. Would I have to pull the 4K RAM module out?

I should have been clearer. What I meant is that you can install 64k modules in any available port. The 71 will reconfigure memory as you add and remove modules and it can address 512k of memory, so that means you could put 4-64k modules in the front port slots and a 128k module in the card reader port, for example.

You can leave the 4k module and install/remove the 32k module as desired. Just follow the rules for removing a memory module. That is, first convert the module to Independent RAM using the FREEPORT command, turn off the 71, then remove the module.

When the module is reinstalled it will have lost it's contents and will be configured as Main RAM.

Dave

[smp]

(06-17-2017 05:33 PM)Dave Frederickson Wrote:  What I meant is that you can install 64k modules in any available port. The 71 will reconfigure memory as you add and remove modules and it can address 512k of memory, so that means you could put 4-64k modules in the front port slots and a 128k module in the card reader port, for example.

Thanks very much, Dave, for your assistance. I have been getting confused about modules and ports. Your explanation clears that up for me.

smp