Revise README with new sections and clarifications

Updated the README to improve clarity and structure, including a new Table of Contents and expanded sections on features and supported hardware.

Author: IanSeyler

README.md

@@ -6,24 +6,56 @@ _Just enough kernel_
 
 Official repo of the BareMetal [exokernel](http://en.wikipedia.org/wiki/Exokernel). It's written from scratch in Assembly, designed for x86-64 hardware, with no dependencies except for the virtual/physical hardware. An ARM and/or RISC-V rewrite would be considered once hardware is standardized.
 
+### Table of Contents
 
-## What is this?
+- [What it is](#what-it-is)
+- [Key features](#key-features)
+- [Supported hardware](#supported-hardware)
+- [Try it out](#try-it-out)
+
+## What it is
 
 BareMetal is a _very_ lean kernel. The name is a play on the phrase "bare metal" which means to run directly on physical or virtualized hardware. BareMetal also only offers the "bare essentials" required for a working operating system.
 
-BareMetal provides basic support for symmetric multiprocessing, network, and drive access via a low-level abstraction layer.
+BareMetal provides basic support for symmetric multiprocessing, network, and storage access via a low-level abstraction layer.
 
 ![BareMetal Model](./doc/BareMetal-Model.png)
 
 
-### Key features
+## Key features
 * **64-bit**: Make use of the extra-wide and additional registers available in 64-bit mode.
 * **Mono-processing, multi-core**: The system is able to execute a single program but can spread the work load amongst available CPU cores.
-* **Extremely tiny memory footprint**: A minimal bootable image, including boot-loader and operating system components, is currently 16K.
+* **Extremely tiny memory footprint**: The kernel binary is less than 32KiB. BareMetal uses 4 MiB of RAM while running. The majority of RAM usage is for required memory structures for operating in 64-bit mode, drivers, CPU stacks, and system buffers.
 * **Physical and virtual hardware support** with full virtualization, using [x86 hardware virtualization](https://en.wikipedia.org/wiki/X86_virtualization) whenever available (it is on most modern x86-64 CPU's). In principle BareMetal should run on any x86-64 hardware platform, even on a physical x86-64 computer, given appropriate drivers. Officially, we develop on [QEMU](http://www.qemu.org) and [VirtualBox](https://www.virtualbox.org), which means that you can run BareMetal on both Linux, Microsoft Windows, and Apple macOS.
 
-
-## Try it out!
+## Supported Hardware
+
+* CPU
+  * Multi-core on 64-bit x86 systems (Intel/AMD)
+* Bus
+  * PCIe
+  * PCI
+  * xHCI (USB 3)
+* Network
+  * Gigabit
+    * Intel 8254x Gigabit (e1000)
+    * Intel 8257x Gigabit (e1000e)
+    * Realtek 816x/811x Gigabit (rtl8169)
+  * 10 Gigabit
+    * Intel 8259x 10 Gigabit (ixbge)
+  * Virtual
+    * Virtio-Net
+* Storage
+  * NVMe
+  * AHCI (SATA)
+  * IDE
+  * Virtio-Blk
+* HID (Human Interface Devices)
+  * PS/2 Keyboard
+  * PS/2 Mouse
+  * USB Keyboard
+
+## Try it out
 
 See the [BareMetal-OS](https://github.com/ReturnInfinity/BareMetal-OS) repo for a full build environment.