# Hardware Identification and Issues

## Kernel Messages (dmesg)

```bash
# View all kernel messages
dmesg

# With human-readable timestamps
dmesg -T

# Filter by facility and level
dmesg -f kern -l warn

# Search for specific info
dmesg | grep "Memory"
dmesg | grep BOOT_IMAGE

# View via journalctl
journalctl -k
```

## CPU Information

```bash
# Quick CPU summary
lscpu

# Key fields:
# - Architecture (x86_64)
# - CPU(s) - logical cores available
# - Thread(s) per core - hyperthreading
# - Core(s) per socket
# - Socket(s) - physical CPUs
# - NUMA node(s)
# - Virtualization support (VT-x, AMD-V)
# - Cache sizes (L1d, L1i, L2, L3)
# - Flags - CPU feature flags
```

## Memory Information

```bash
# Physical memory details (type, speed, location)
dmidecode -t memory

# Key fields:
# - Size (e.g., 8192 MB)
# - Form Factor (DIMM, SODIMM)
# - Type (DDR3, DDR4)
# - Speed (e.g., 1600 MHz)
# - Locator (slot name)

# Quick memory overview
free -h

# Detailed memory stats
cat /proc/meminfo
```

## Storage Devices

```bash
# List SCSI-compatible devices (SSD, USB, SATA, SAS)
lsscsi
lsscsi -v  # verbose

# Detailed disk info
hdparm -I /dev/sda

# Block device list
lsblk

# Disk partitions
fdisk -l
```

## PCI and USB Devices

```bash
# List PCI devices
lspci
lspci -v    # verbose
lspci -vvv  # very verbose

# List USB devices
lsusb
lsusb -v    # verbose

# Device tree
lsusb -t
```

## Hardware Error Reporting (rasdaemon)

```bash
# Install and enable
yum install rasdaemon
systemctl enable --now rasdaemon

# View error summary
ras-mc-ctl --summary

# List all errors
ras-mc-ctl --errors

# Show corrected/uncorrected counts
ras-mc-ctl --error-count

# Memory layout
ras-mc-ctl --layout

# EDAC driver status
ras-mc-ctl --status
```

## Memory Testing (memtest86+)

For BIOS systems:

```bash
# Install memtest86+
yum install memtest86+

# Setup boot entry
memtest-setup

# Update GRUB
grub2-mkconfig -o /boot/grub2/grub.cfg

# Reboot and select memtest86+ from boot menu
```

## DMI/SMBIOS Information

```bash
# All DMI info
dmidecode

# Specific types
dmidecode -t bios
dmidecode -t system
dmidecode -t baseboard
dmidecode -t processor
dmidecode -t memory
dmidecode -t cache
```

## System Information Files

| File | Contents |
|------|----------|
| `/proc/cpuinfo` | CPU details per core |
| `/proc/meminfo` | Memory statistics |
| `/proc/interrupts` | IRQ assignments |
| `/proc/ioports` | I/O port assignments |
| `/proc/iomem` | Memory-mapped I/O |
| `/sys/class/` | Device class info |
| `/sys/devices/` | Device topology |

## Quick Hardware Summary Script

```bash
#!/bin/bash
echo "=== CPU ==="
lscpu | grep -E "Model name|Socket|Core|Thread"

echo "=== Memory ==="
free -h

echo "=== Storage ==="
lsblk

echo "=== Network ==="
ip link show

echo "=== PCI ==="
lspci | grep -E "Network|VGA|Audio"
```