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Why was the DOS clock device renamed from CLOCK into CLOCK$?

Quick partial answer: CON, LST, PRN and AUX (*1) are names inherited from CP/M, either direct form its BIOS or CP/M's main file handling utility PIP (*2). NUL was add with DOS. DOS 1.x added ...
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37 votes

Why did CP/M and MS-DOS use the BIOS instead of their own drivers to access hardware?

The BIOS originated as part of the CP/M operating system. It was the "layer" that interfaced directly with the hardware and as such, was usually machine specific. The idea is that, if you ...
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34 votes
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Why have MS-DOS device drivers if the ROM BIOS provides access to the same devices already?

TL;DR: MS-DOS is a vendor independent DOS and IO.SYS is its abstraction layer encapsulating all machine dependent parts. If DOS would direct access the ROM BIOS it would be specific to the IBM-PC, ...
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30 votes

Did terminals (e.g. VT100) require a terminal driver on the host computer?

Different terminals didn’t (and don’t) use different kernel-level drivers. In Unix-style systems, the kernel does provide some terminal-related features, called line disciplines and the TTY layer ...
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26 votes
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How does Windows 9x determine which disk drivers correspond to which BIOS disks/DOS drive letters?

By their contents. When Windows boots, the I/O Supervisor VxD (IOS) uses BIOS interrupt 0x13 services to read sector 0 (the Master Boot Record) of each drive. It then looks at two bytes at offset ...
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26 votes

Why are these DOS console drivers wasting precious bytes?

As Michael Karcher already points out in a comment, the shown sequences are quite typical for a compiler at the time. I'd say most likely C. That or use of a standardized macro set. This is not only ...
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25 votes
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Sound driver for DOS or Windows 3.x that used the PC speaker?

It was a DOS-Windows 3.x and DOS-Windows 9x/ME thing. It was a driver named speaker.drv, written by Microsoft. It turned off interrupts for significant periods of time, which caused I/O problems ...
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25 votes

Why was the DOS clock device renamed from CLOCK into CLOCK$?

As Raffzahn explains, the clock device driver was added in DOS 2.0. CON, AUX, etc. were device names already present in DOS 1.0, some of them even earlier in CP/M; these names couldn’t be changed to ...
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24 votes

What really is a sound card driver in MS-DOS?

Summary: Real ISA Sound Blaster cards don't need any drivers to initialise or support them. Later PNP Sound Blasters (SB16/AWE) and clones may need a driver that performs one-time initialisation. ...
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20 votes

Why did CP/M and MS-DOS use the BIOS instead of their own drivers to access hardware?

CP/M was hardware independent - there was no notion of a reference machine (as the IBM PC was for MS-DOS), so CP/M could not provide drivers. The hardware producer had to develop the drivers and ...
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17 votes
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Why didn't PostScript eliminate the need for printer drivers?

they save every program from needing its own separate encyclopedic knowledge of every printer on the market. But then came PostScript, the theory behind which was that you would prepare a printable ...
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16 votes

What really is a sound card driver in MS-DOS?

Most PCI soundcards do not have hardware support for games and other applications that expect a SoundBlaster or AdLib to be present. Older cards made a special effort to provide what's known as "...
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15 votes
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Was there ever a Linux kernel driver for accessing disks via BIOS?

To my knowledge, no such driver has ever been written. Since the very earliest versions, Linux has been a pure 32-bit protected-mode kernel that drove most devices (including disk controllers) ...
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13 votes

Why did CP/M and MS-DOS use the BIOS instead of their own drivers to access hardware?

The simple answer is that they just didn't need them! Why reinvent the wheel, when the required interface is already provided by the ROM BIOS? This allows the operating system to be more portable and ...
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13 votes

Why didn't PostScript eliminate the need for printer drivers?

Cost There are significant licensing costs and equipment costs. I'm sure PostScript needs quite a bit more RAM & processing than some of the lower levels of PCL and similar printer languages. As I ...
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12 votes

Why didn't PostScript eliminate the need for printer drivers?

PostScript was quite demanding. In the early days a PostScript printer might well be the most powerful computer in the building, hence expensive. University students ran jobs on the printer to get ...
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12 votes
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S-100 bus and device drivers

Like most busses of its time, you had to write your own software to communicate between the cards. The term device driver wasn't widespread at the time, but that is what you were writing. The S-100 ...
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12 votes
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Is there a generic VBE driver available for Windows 3.x?

It seems unlikely that a fully-functional VBE driver for Windows 3.x exists. Microsoft started bundling a VBE driver with the operating system only as late as with Windows XP, by which time the ...
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12 votes
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Why are these DOS console drivers wasting precious bytes?

I come with disappointing news, again. Given that these snippets of assembly code look as if mechanically translated, one might suppose that they indeed were: that they are outputs of a compiler of a ...
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12 votes

Why have MS-DOS device drivers if the ROM BIOS provides access to the same devices already?

First, the terminology. In the context of DOS, the term ‘BIOS’ may refer to either one or sometimes both of two things: (a) the IBM PC firmware stored in the ROM, or (b) one of the halves of the DOS ...
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10 votes

Did terminals (e.g. VT100) require a terminal driver on the host computer?

This was not done by a “driver” at the OS level as you are thinking of it. In Unix, there were drivers that dealt with the RS232 interface and these were surfaced as /dev/tty* devices and dealt with ...
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10 votes
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Why can't VirtualBox install drivers for Windows 95B?

The Windows 95 installation happens in two phases. Assuming you are installing from scratch the first phase runs under a stripped down version of Windows 3.x which runs under the DOS environment you (...
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10 votes

Did terminals (e.g. VT100) require a terminal driver on the host computer?

"It depends". I'm answering this in the context of DEC timesharing systems, since that's the natural habitat of a DEC VT100. There's a hardware device such as a DZ11 terminal multiplexer (8 lines) ...
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10 votes
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How did the BBC sideways ROM software for the AMX mouse process the user port input data to determine x and y movement?

Trying to get more into the specifics of the BBC connection, there is a substantial hint in the user guide: However only 5 bits of the [user] port, and CB1, CB2 are used: This leaves bits 1,3 and 4 ...
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10 votes

How does Windows 9x determine which disk drivers correspond to which BIOS disks/DOS drive letters?

It wasn't anything to do with drive letters, or the Windows NT disc signature in the MBR. DOS-Windows 9x, in particular the infamous wdctrl virtual device driver (often known colloquially and ...
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  • 1,821
10 votes

Why are these DOS console drivers wasting precious bytes?

So my question is: Why did the programmer(s) not write the shortest code possible in an OS that is confined to conventional memory? Because they had deadlines, other things to work on and "good ...
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8 votes

S-100 bus and device drivers

An important thing is that old-style expansion buses - that includes S100, als well as the PC ISA bus and various proprietary buses, had no enumeration capability - a computer system was not aware of ...
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8 votes
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How do I make a Unibus device?

The simplest Unibus card is the G727 Grant Continuity Card, which does nothing except forward certain daisy-chained bus signals from one slot to the next. You can see a picture of one on the ...
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8 votes
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What really is a sound card driver in MS-DOS?

The typical way to provide "driver" services to other programs in DOS is to run a TSR (Terminate and Stay Resident) program installing a software interrupt vector such that running DOS ...
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