On Sep 29, 2025, Greg wrote:
On 2025-09-29, Michael Stone <mstone@debian.org> wrote:On Mon, Sep 29, 2025 at 05:26:54AM -0500, Richard Owlett wrote:Underlying my question was the assumption that when a processor was referred to as 32 or 64 bit, it was a reference to the width of the data bus.Not really, which is why this was a weird/misleading/confusing question. A "bus" is the physical connection between components in a computer. The (basically obsolete) phrase "data bus" referred to the physical connection between the processor and external components. In earlyI thought a 32-bit data bus meant → 4 bytes at once, and 64-bit data bus meant → 8 bytes at once (i.e. the number of bits capable of being transferred over the bus in parallel, simultaneously).
This was true for some period of time; but I think it started becoming less true around the days of the 386 or 486, as they were 32-bit processors, but many peripherals of the era were still only able to send data in 16-bit chunks.
No point in having a 32-bit wide data bus when things like PATA or ISA cards were only 16bit max.
I *believe* PCI (and for a time, AGP) were capable of running in 32-bit modes, but then they also died off to serial interfaces (PCIe, SATA, etc.)
As far as I am aware, the only remaining parallel data bus on a PC is the connection to RAM.
-- |_|O|_| |_|_|O| Github: https://github.com/dpurgert |O|O|O| PGP: DDAB 23FB 19FA 7D85 1CC1 E067 6D65 70E5 4CE7 2860
Attachment:
signature.asc
Description: PGP signature