68kMLA Classic Interface

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Dual PDS in SE
Posted by: marchie on 2024-10-24 16:14:35 Is someone making new PDS riser cards that would let us put more than one card in an SE? YES, I know I likely need to remove a drive or two. I've done that, as I'm using an external BlueSCSI for drive purposes. I have an Accelerator card in an SE already and would like to add the ethernet card if possible.
Posted by: Snial on 2024-10-25 01:17:11 Is someone making new PDS riser cards that would let us put more than one card in an SE? YES, I know I likely need to remove a drive or two. I've done that, as I'm using an external BlueSCSI for drive purposes. I have an Accelerator card in an SE already and would like to add the ethernet card if possible. The issue will be decoding, surely? PDS isn't NuBus (which was also only for Mac IIs, Quadras and the PowerMac x100 series) and not plug-n-play; so there's only one possible decoding 'slot', which all PDS peripherals will decode to. Also, the SE ROM almost certainly only looks at a single memory region for a PDS, so even if you built an extra slot; it wouldn't see the second one.
Posted by: cheesestraws on 2024-10-25 01:40:39 The issue will be decoding, surely? Yup - and no slot manager to do pseudoslot designs too like you can in the SE/30 (which is largely how passthrough cards on the SE/30 work, IME). Also, the SE ROM almost certainly only looks at a single memory region for a PDS, so even if you built an extra slot; it wouldn't see the second one No slot manager on the SE, so no declroms; the ROM doesn't do anything with the PDS slot at all AFAIK... I have an Accelerator card in an SE already and would like to add the ethernet card if possible. This is one of the reasons why Radius had a magicbus slot on their accelerators, which passed through most of the PDS to another card which they knew wasn't going to collide with it
Posted by: Franklinstein on 2024-10-26 02:25:51 I have seen examples of double PDS devices used on LCs before. I think the secret is to design the cards together so that there are no conflicts, and even then it's usually a CPU upgrade paired with, typically, an Ethernet card (where basically, the second PDS slot talks directly to the upgrade and so is a true PDS, not a pass-through). There may be some obscure cards which run two separate devices on a single PDS (Ethernet and video, or two separate video components) but they're uncommon and need careful configuration. Most of the difficulty is in bus etiquette where the respective devices politely negotiate bus master status, properly request and release the bus, etc., rather than just assume they have exclusive access to do whatever they want.
Posted by: joshc on 2024-10-26 04:37:09 I have an Accelerator card in an SE already and would like to add the ethernet card if possible. Look into Scuznet to achieve this without needing PDS
Posted by: cheesestraws on 2024-10-26 05:06:55 Yes, an internal scuznet is how I did this in a machine with another PDS card in.
Posted by: marchie on 2024-10-26 14:30:26 Oooh I didn’t realize the SE wasn’t already prepared for this. I knew the SE30 was….
Posted by: cheesestraws on 2024-10-26 14:35:09 Oooh I didn’t realize the SE wasn’t already prepared for this. I knew the SE30 was…. They are very, very different beasts as soon as you get to the logic board.
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