1 00:00:00,060 --> 00:00:03,190 ‫In this course, you will learn all about colonel development. 2 00:00:03,240 --> 00:00:10,440 ‫We start off small by learning Anthos real mode where we develop an actual bootloader, the boot from 3 00:00:10,440 --> 00:00:11,420 ‫real hardware. 4 00:00:11,640 --> 00:00:16,140 ‫We actually boots it on our real computers and we see hello world on the screen. 5 00:00:16,350 --> 00:00:17,250 ‫And there we go. 6 00:00:17,260 --> 00:00:18,000 ‫Hello world. 7 00:00:18,370 --> 00:00:20,130 ‫This program is self-sufficient. 8 00:00:20,310 --> 00:00:22,540 ‫It requires no operating system. 9 00:00:22,560 --> 00:00:24,390 ‫It is bootable code. 10 00:00:24,930 --> 00:00:27,960 ‫Your journey starts here throughout real NMO. 11 00:00:27,990 --> 00:00:33,140 ‫We also load sectors from our hard disk into memory. 12 00:00:33,870 --> 00:00:41,490 ‫Now, real mode is a compatibility mode by Intel that allows Intel processors to run as they ran maybe 13 00:00:41,490 --> 00:00:42,930 ‫20 or 30 years ago. 14 00:00:43,020 --> 00:00:45,380 ‫Real mode is a legacy mode by Intel. 15 00:00:45,480 --> 00:00:48,440 ‫It is fairly limited, but learning it is essential. 16 00:00:48,450 --> 00:00:54,240 ‫After we work with Intel's legacy McCole remote, we move to what's known as protected mode, which 17 00:00:54,240 --> 00:00:57,750 ‫is what all 32 bit operating systems use. 18 00:00:57,760 --> 00:00:59,760 ‫You are taught all about protected mode. 19 00:00:59,760 --> 00:01:06,240 ‫In this course, you learn all about virtual memory, memory virtualization, mapping virtual addresses 20 00:01:06,240 --> 00:01:07,560 ‫to physical addresses. 21 00:01:07,860 --> 00:01:10,560 ‫Our process is all shared the same addresses. 22 00:01:10,740 --> 00:01:12,150 ‫How is this even possible? 23 00:01:12,360 --> 00:01:18,060 ‫Or you will find out in this course we can have multiple processes running and they all share the same 24 00:01:18,060 --> 00:01:18,990 ‫memory addresses. 25 00:01:19,290 --> 00:01:20,310 ‫This is amazing. 26 00:01:20,310 --> 00:01:23,490 ‫It's called paging and this is all taught to you. 27 00:01:23,760 --> 00:01:29,100 ‫And by using paging, we can prevent processes from seeing certain parts of memory. 28 00:01:29,310 --> 00:01:35,520 ‫It's a great security feature and it allows us to compile all user programs at the same address. 29 00:01:35,610 --> 00:01:37,140 ‫You're going to learn all about this. 30 00:01:37,140 --> 00:01:41,460 ‫In this course, your kernel will be capable of handling the entire system memory. 31 00:01:41,880 --> 00:01:44,820 ‫It'll be able to allocate memory to different processes. 32 00:01:44,820 --> 00:01:48,230 ‫It'll be able to restrict memory access from certain processes. 33 00:01:48,270 --> 00:01:53,370 ‫This course shows you how to create processes for your operating system and load them into memory and 34 00:01:53,370 --> 00:01:53,850 ‫run them. 35 00:01:54,270 --> 00:01:55,920 ‫And we can have multitasking. 36 00:01:56,160 --> 00:01:56,820 ‫In this course. 37 00:01:56,820 --> 00:01:59,130 ‫You're taught how to make a multitasking kernel. 38 00:01:59,610 --> 00:02:03,240 ‫We can have multiple processes running at the exact same time. 39 00:02:03,240 --> 00:02:06,540 ‫Our processes can also be of the el-Fadl format. 40 00:02:06,840 --> 00:02:10,050 ‫OK, in this course we support two types of loading. 41 00:02:10,050 --> 00:02:13,920 ‫We can load binary files and we can load our files. 42 00:02:14,160 --> 00:02:20,250 ‫Now, all Linux programs are our files we're implementing and our to that can actually load files into 43 00:02:20,250 --> 00:02:20,750 ‫memory. 44 00:02:20,970 --> 00:02:23,520 ‫Now, I'm not saying you will be able to run Linux programs. 45 00:02:23,520 --> 00:02:29,130 ‫What I am saying is you will be able to load our files, which is fantastic because our files have headers. 46 00:02:29,370 --> 00:02:33,200 ‫They have information describing the process and how it should be laid in memory. 47 00:02:33,510 --> 00:02:36,420 ‫This is much more efficient than loading just binary files. 48 00:02:36,630 --> 00:02:41,610 ‫So this course takes you a step further by creating an actual elf LoDo. 49 00:02:41,640 --> 00:02:44,190 ‫You're also taught how to handle malicious programs. 50 00:02:44,310 --> 00:02:45,720 ‫Not all programs are nice. 51 00:02:45,990 --> 00:02:48,990 ‫What if someone writes a program that tries to modify your kernel? 52 00:02:49,470 --> 00:02:54,270 ‫What in our kernel, the kernel will know that you've done that and it will kill the process. 53 00:02:54,300 --> 00:03:00,810 ‫This is achieved by using, paging and setting up certain security rules on the different memory that 54 00:03:00,810 --> 00:03:03,870 ‫the process can access if it violates those rules. 55 00:03:04,110 --> 00:03:09,930 ‫And interrupt exception is called and our kernel will say, no, no, no, it'll kill the process and 56 00:03:09,930 --> 00:03:14,160 ‫unload it from memory, you're going to learn all of that and how to do that in this course. 57 00:03:14,340 --> 00:03:17,820 ‫You're also going to learn how to handle program crashes. 58 00:03:18,420 --> 00:03:21,810 ‫Sometimes programs do things by accident that they shouldn't. 59 00:03:21,930 --> 00:03:24,870 ‫Right now we need to handle that. 60 00:03:25,080 --> 00:03:28,110 ‫If we don't handle that, the process stays loaded in memory. 61 00:03:28,500 --> 00:03:34,350 ‫Now, you're taught how to unload the program when it crashes and how to detect when a program is crashed. 62 00:03:34,410 --> 00:03:40,020 ‫By the end of this course, you can expect to have a fully working 32 bit kernel, an operating system 63 00:03:40,170 --> 00:03:41,490 ‫with an interactive shell. 64 00:03:41,850 --> 00:03:43,230 ‫OK, think a command prompt. 65 00:03:43,230 --> 00:03:44,730 ‫You know, you can type into command prompt. 66 00:03:45,120 --> 00:03:47,370 ‫That's our interactive shell, something like that. 67 00:03:47,370 --> 00:03:52,020 ‫Your operating system, Colonel, will also be a multitasking operating system, Colonel, as I've already 68 00:03:52,020 --> 00:03:52,380 ‫said. 69 00:03:52,740 --> 00:03:55,650 ‫So we'll have multiple processors running at the same time. 70 00:03:55,890 --> 00:03:58,200 ‫You're going to learn how to do that in this course. 71 00:03:58,470 --> 00:04:02,850 ‫And by the end of this course, you will understand, Colonel, and operating system development very 72 00:04:02,850 --> 00:04:08,400 ‫well and you'll be able to take what you've learned to improve your colonel, adding new features. 73 00:04:08,670 --> 00:04:12,750 ‫And who knows, maybe that'll be the next the next enroll in this course today.