mdj wrote:
On Feb 4, 5:00 am, "Michael J. Mahon" <mjma...@aol.com> wrote:The Slinky design only provides efficient sequential access to the expansion memory, and is therefore best suited for RAM disks and certain "swapping"-style memory managers, like Appleworks uses. In fact, I've always theorized that the Slinky design was inspired by Appleworks, which was the premier Apple II app that could benefit from memory expansion.It was also released early enough that there were a lot of ][/+ machines still in service, and without motherboard modification bank- switched designs are limited to the language card area, not to mention the complications with cooperating with existing slot-0 language cards.
Good point. But even bank switching a meg in 16KB banks would be just as fast and as easy as the Slinky architecture for sequential accesses, and it would be more versatile--just an extension of the Saturn scheme. But there wasn't much of a market for >128KB memory expansion pre-//e, because Appleworks was the primary "consumer" of expansion memory. Certainly there were some Pascal users who would have wanted a larger RAM disk, but they must have been a miniscule number compared to the Appleworks armies who craved a larger desktop. (I was one of those who might have been interested, since I used the Plusworks patches to run Appleworks on my ][+. ;-) It's actually quite disappointing how little real use there is for expansion memory--another chicken and egg problem in the marketplace. And if today is any indication, there were a lot more third party RAMworks-style cards in use than Slinky-style expansions. If there had been a new version of ProDOS that loved memory expansion, and tools to make it easy for applications to use, memory expansion might have been more useful and more popular. Of course, a single architecture would also have helped. ;-) I'd vote for bank switching over Slinky in an instant. For sequential block access, the bank-switched architecture is nearly as fast as the Slinky architecture, and bank switching also supports code execution and fast random accesses within a bank, which Slinky does not. -michael NadaNet and AppleCrate II: parallel computing for Apple II computers! Home page: http://home.comcast.net/~mjmahon "The wastebasket is our most important design tool--and it's seriously underused."