myos

Your run command isn't mounting your current directory, unless it's a typo you haven't corrected yet. When I posted this, it read sudo docker run --rm -it -v Spwd:/root/env myos-buildenv .

I think you meant $PWD or $(pwd) , like this:

You have two problems

1. scanf("%s", &command); here variable command requires a buffer of some size greater than 1.

Use as below
#define COMMAND_SIZE 1024 and declare some thing like char command[COMMAND_SIZE] = {0}

1. I think you are trying to read multiword string, that is not possible with the way you used scanf("%s", command); even if command has sufficient size.

Better use fgets(command, sizeof(command), stdin); to read multiword strings.

In short you need some thing like this:

You need to use offsetWidth and offsetHeight, which takes into account borders, padding etc,.

Like so:

Try window.getComputedStyle(searchBox_input).visibility (MDN)

The solution (thanks to @MichaelPetch) was to setup segment registers after loading the GDT. My new entry point:

It's caused because of a common misinterpretation of the El Torito CD-ROM boot specification which says that emulated bootsectors should be loaded at the "traditional segment of 7C0" by default. It doesn't say that a non-traditional starting address of 07C0:0000 should be used instead of the traditional 0000:7C00, but BIOS writers have interpreted this as a requirement nonetheless.

While you can assume that your bootsector is loaded at a linear address of 00007C00 and that the BIOS starts execution of your code at the first byte of the bootsector, you can't assume any particular value of CS:IP. While most bootsectors can be written not to depend on the segment value loaded into CS, as near JMP and CALL instructions are relative, if yours does then you'll need to put a far JMP instruction your code to ensure CS is loaded with the expected segment value:

The original Operating System code required effort to determine the root cause of this problem. The example makes it easier for people to potentially spot the culprit. Finding this problem in the original code took some effort.

The primary problem is that you have placed the Multiboot section (with the Multiboot2 header) at Virtual Memory Address (VMA) 0x500 in the linker script with this:

According to the osdev wiki, the method of enabling the A20 line in protected mode varies wildly form one chipset to another. And in some it can even be enabled by the bios/bootrom on boot. Therefore the common practice is to first write a routine that can check if the A20 line is enabled (by writing data to an accessible ram region and looking for that data to be mirrored in higher ram addresses)which you did, and your approach seems correct as far as i can tell. Only if the bios/bootrom has not enabled it do you try other methods.

When your PC boots, the A20 gate is always disabled, but some BIOSes do enable it for you, as do some high-memory managers (HIMEM.SYS) or bootloaders (GRUB). Once you have this check, you can then try all the methods foi wnabling it one by one and see which one works for the system

The recommended procedure for enablig it is:

Because there are several different methods that may or may not be supported, and because some of them cause problems on some computers; the recommended method is to try all of them until one works in the "order of least risk". Essentially:

We cannot Elimainate Mutual Exclusion then why is it one of the condition ??

We cannot eliminate mutual exclusion in cases where we are dealing with non-shareable resources. So, it simply emphasizes that for special cases when we dealing with resources like tap drive and printer, which are inherently non-shareable, then we have to look at eliminating one of the other three options to prevent deadlock.

Now Critical Section does not always mean that we are talking about physical resources. It can also mean that we are talking about a piece of code. And variables are resources that are inherently shareable resources. So in such cases we can eliminate mutual exclusion to prevent deadlock. But keep in mind thats rarely done, because if we had ensured mutual exclusion in the initial design, it was there to ensure correct implementation. So just to make you aware that deadlock could be prevented by preventing mutual exclusion, but it does not mean that its practically prevalent.