Do I need ISA DMA when re-creating a new retro PC?

All off topic discussions go here. Everything from the funny thing your cat did to your favorite tv shows. Non-programming computer questions are ok too.
Post Reply
technix
Member
Member
Posts: 28
Joined: Sun Jun 16, 2013 10:13 am

Do I need ISA DMA when re-creating a new retro PC?

Post by technix »

As the title suggest, I am thinking about creating a new retro PC using some NOS NEC V20 chips and make it DOS compliant. Given that I have no plan of supporting any kind of floppy (Instead I have a USB interface chip that supports sector-level and file-level access to USB mass storages,) I use XT-SATA hard card (XT-IDE + a JMicron IDE to SATA chip + mSATA SSD all on one board) for local mass storage, and my board uses modern SRAM for system memory (which means no DRAM refresh,) do I even need to have the 8037 ISA DMA onboard?
nullplan
Member
Member
Posts: 1790
Joined: Wed Aug 30, 2017 8:24 am

Re: Do I need ISA DMA when re-creating a new retro PC?

Post by nullplan »

Sound? I do seem to remember the SoundBlaster cards requiring DMA. At least, I haven't found any PIO drivers. Of course, if you plan on only beeping the Speaker then that's not an issue.
Carpe diem!
Octocontrabass
Member
Member
Posts: 5568
Joined: Mon Mar 25, 2013 7:01 pm

Re: Do I need ISA DMA when re-creating a new retro PC?

Post by Octocontrabass »

Making hardware that boots DOS is easy: you just need an x86 CPU and something vaguely resembling a BIOS. DOS doesn't actually care too much about PC hardware.

Software that runs on DOS tends to care a lot more about PC-compatible hardware. However, thanks to IBM's "clever" hardware design, the DMA controller is used almost exclusively for peripherals like the floppy disk controller or the SoundBlaster. If you're not going to support peripherals that use DMA, you don't need a DMA controller. (You might need something that pretends to be a DMA controller to satisfy software that wants to fiddle with it, though.)
Post Reply