128
No. The FAT12/16/32 filesystems store the filename and extension together in a fixed-length 11 character field. The first 8 characters of this field is the filename and the last 3 is the extension. Trailing space characters in both the filename proper and its extension are ignored. The '.' character between the filename and extension is implicit. ...
117
The text-mode cursor isn’t a character, it’s managed separately by the video output circuitry (which is how it keeps blinking even when your computer is busy or locked up). It can be enabled or disabled, and its size can be determined — at least, its start and end scanlines, which determine its height; the cursor always occupies the full width of a character ...
96
The short answer is that DOS was designed to be similar to CP/M, and drawing a quote from here:
While 8-bit programs could not run on 16-bit computers, Intel
documented how the original software developer could mechanically
translate an 8-bit program into a 16-bit program. Only the developer
of the program with possession of the source code could ...
94
This is covered largely in the history section of Wikipedia’s entry on newlines. Basically there are two primary lineages of operating systems leading to modern-day desktop usage: Windows on the one hand, and Unix-like systems on the other.
Windows descends from MS-DOS (because initially it was implemented on top of DOS), which itself inherits much of its ...
94
The honorific "Ms." didn't always exist. It was popularized by the feminist movement as an alternative to Miss (woman is not yet married) and Mrs. (woman is married),
But it took feminist activist Sheila Michaels to bring [the "Ms." honorific] into consciousness of the feminists of the 1960s and '70s. Ms: The honorific with unintended meaning
The idea ...
91
Bootable game disks do exist for the IBM PC. Conflict in Vietnam is an example of such a game. As can be seen on page 8 of the manual, the game boots directly without loading DOS first.
The main reason it wasn't common was for compatibility. A self booting game has to have its own drivers for all the hardware it wants to support. As PCs quickly diversified ...
88
There were a number of factors involved.
Windows 3.0 introduced a more refined user interface than available in Windows 2.0: more colours, proportional fonts everywhere, smaller icons, and MDI windows (multiple document windows inside an application window)... This made it "obviously" better than plain DOS to many users. Reviewers back in the day ...
79
For Win16 programs, Windows implemented co-operative multitasking. Its implementation was based upon the "message loop" architecture of every Windows program.
The duty of every program was to endlessly run in a loop in which a call to the GetMessage function was performed. This function call looks whether a message to this process is in the queue. ...
78
Stephen Kitt covers the bases well, but I think the majority of the reason relates to fact that Windows 3.0 finally brought 286 protected mode execution to the masses. Even though the 80286 was first released in 1984, Windows 3.0 was the first mainstream platform that actually ran it in protected mode. That made it the first mainstream platform that could ...
68
TL;DR;
Using INT comes not only natural due the way the 8086 is designed, but was as well intended by Intel as OS entry point, much like a Supervisor Call (SVC) on /360 type mainframes:
(Excerpt from the October 1979 Intel 8086 Family User's Manual page 2-28.)
Software-initiated interrupt procedures may be used as service routines ("supervisor calls&...
57
Since you are using MS-DOS 6.22 you can abuse the CHOICE command to introduce a set timed delay by piping the output of a REM statement to the choice command, leaving it with no way to complete other than via the /T timeout option.
Example from Rob van der Woulde's Scripting Pages:
REM | CHOICE /C:AB /T:A,10 >NUL
The CHOICE command never actually gets ...
57
Because it used to be necessary.
While a battery-powered real-time clock is standard today, this wasn’t always the case. The very first IBM 5150 did not include an RTC chip. This meant that when the computer was turned off, there was no hardware inside to maintain the clock. A number of third-party extension boards were available to overcome this problem; ...
52
The cursor on the CGA, MDA, EGA, and VGA cards was a hardware sprite
generated on the earlier cards by the 6845 video controller, and on later
cards by a chip that emulates the 6845. That chip has an address counter
that is used to fetch data from memory, as well as a line counter and a
cursor-state latch. It also has a programmable registers for cursor ...
51
I’m not sure about OS manufacturers, but hardware manufacturers still use DOS, in at least two scenarios visible to the general public:
firmware upgrade CD images;
bare-bones enterprise laptop and workstation setups (e.g. from HP or Lenovo, “bare-bones” as in “with FreeDOS as the only installed operating system”; in some countries you’ll need a business ...
49
TL;DR: It was IBM's idea.
IBM never intended to buy any of the software they acquired for the PC - and MS never intended to supply any OS beside Xenix.
But MS (Paul Allen) soon recognized the potential business and acted accordingly.
The Long Read
IBM had no interest whatsoever in setting up a basic software development for the PC. The strategy was to ...
49
No, it didn't. MS-DOS never bothered to zero out allocated memory, as there was no security reason to do so like there is in a multi-user operating system. It was up to the C runtime startup code to zero out the BSS segment.
For example, from the Borland C++ 3.1 startup code:
; Reset uninitialized data area
xor ax, ax
...
46
Traditionally, operating shells are relatively independent of the operating system’s function and the operating system can operate without a shell. Most shells have two modes of operation, interactive mode where they manage the command line and execute commands entered interactively, and batch mode where they run scripts. They’re “standard” programs which ...
45
No, DOS won't use any additional CPU (*1) ever.
(Though it might run faster due them new CPUs being faster)
Quite the same way as DOS doesn't take advantage of the extended memory or additional instructions.
DOS is a
Single CPU
Single User
Single Task
Single Program
Real Mode
8086
operating system.
Even through it got a few extensions over time to tap a ...
45
Unreal Megademo, Future Crew, 1992 possibly? Certainly has all the elements you mention.
44
They didn't share any source, no. However, the TITLE directive twenty lines or so down from the top in both XENIX.ASM and XENIX2.ASM explains what this is:
TITLE XENIX - IO system to mimic UNIX
Pre-2.x MS-DOS was somewhere between heavily inspired by CP/M and a complete rip-off of it. But with 2.x they decided to go in a quite different direction, and ...
43
There's actually two versions IO.SYS and COMMAND.COM used with Windows ME. The normal "crippled" versions used to boot from hard disks, and the "Emergency Boot Disk" versions use to boot from floppies. It's those later EBD versions that are embedded in diskcopy.dll under Windows XP, Windows Vista, Windows 7 and Windows 8.
The EBD versions are crippled in ...
42
Found a great answer on Super User that explains it really well!
Windows 3.1 uses cooperative multi-tasking – meaning that each
application that is in the process of running is instructed to
periodically check a message queue to find out if any other
application is asking for use of the CPU and, if so, to yield control
to that application. However,...
41
The Meltdown attack is about figuring out what's in protected memory (typically, kernel memory) by arranging for it to be speculatively read, and then looking for residual side effects after the speculative read is discarded.
MS-DOS is immune to Meltdown because it doesn't do memory protection. If you want to figure out what's in RAM, you can simply look.
...
41
ECHO ON was chosen as the default setting when interpreting batch files to preserve backwards compatibility. In PC-DOS 1.0, COMMAND.COM displayed each command as it interpreted it, and this couldn’t be disabled. ECHO was added in PC/MS-DOS 2.0, with a dual purpose (displaying messages, and controlling the display of batch file commands); its default is ON so ...
40
Later versions of DOS tended to use more memory. On 386 systems, or systems with EMS memory, this wasn't a huge issue because dos could be configured to use memory outside of the standard 640K region for a large proportion of its use, but on 286 machines (which couldn't run EMM386 to emulate EMS memory, but generally didn't have any real EMS) this wasn't ...
40
I can think of a number of reasons:
DOSKEY isn’t specifically tied to COMMAND.COM; it provides history for any program which uses the same input functions as COMMAND.COM, and one could imagine wanting to run DOSKEY with another command interpreter (although the most popular alternative command interpreter, 4DOS, already included equivalent features);
DOSKEY ...
36
Fonts for text rendered to the screen or paper in a graphics mode would simply be data shipped with the application. If this was perceived to be non-copy-able, it is likely because it was not (obviously) in a standard font format, and perhaps intentionally obfuscated.
It is also worth noting that VGA cards permitted relocating the text mode character ...
36
MS DOS inherited many of its commands from CP/M. CP/M was designed with influences from classic minicomputer operating systems, especially those produced by DEC. Many of these systems dated back to the mid to late 1960s and were designed to run in very little space, e.g. DOS-11 ran on a PDP 11 with 8 KB of RAM. They were also mostly designed primarily ...
33
The first game sold for use on the IBM PC was Microsoft Adventure, which was available on the day the IBM PC was released (it was part of the launch, along with VisiCalc, Easywriter etc.). It was developed by Gordon Letwin (later of OS/2 fame) in 1979, based on the Colossal Cave mainframe game. It didn’t run on DOS though, it was a “booter” — you booted the ...
33
I remember CDD as a 4DOS command, which would have been available in the Norton Utilities as NDOS. JP Software’s other shells also implement CDD, so 4OS2 and 4NT users would probably recognise it too.
There is at least one batch file implementation of CDD too, developed by Gary Mays in 1996, and provided as part of his “M” batch file enhancer (which I can’t ...
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