101.1 Determine and configure hardware settings
Nerd Cafe
This involves working with:
BIOS/UEFI
Boot process
Hardware devices (PCI, USB, CPU info, etc.)
Tools like
lspci,lsusb,dmesg,lsmod,modprobe, etc.
Step 1: Understand the Role of BIOS/UEFI
BIOS (Basic Input/Output System) or UEFI (Unified Extensible Firmware Interface) initializes hardware before the OS starts.
Tasks:
Configure boot device order
Enable/disable onboard devices
Manage virtualization support
Check CPU features like Hyper-Threading, VT-x, etc.
You must access BIOS/UEFI before the OS boots (usually by pressing
Del,F2, orEscat boot time).
Step 2: View Hardware Information from Within CentOS
2.1 Check CPU Info
[root@nerd-cafe ~]# cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 58
model name : Intel(R) Core(TM) i7-3632QM CPU @ 2.20GHz
stepping : 9
microcode : 0x21
cpu MHz : 2195.019
cache size : 6144 KB
physical id : 0
siblings : 1
core id : 0
cpu cores : 1
apicid : 0
initial apicid : 0
fpu : yes
fpu_exception : yes
cpuid level : 13
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss syscall nx rdtscp lm constant_tsc arch_perfmon nopl xtopology tsc_reliable nonstop_tsc eagerfpu pni pclmulqdq ssse3 cx16 pcid sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm ssbd rsb_ctxsw ibrs ibpb stibp fsgsbase tsc_adjust smep arat md_clear spec_ctrl intel_stibp flush_l1d arch_capabilities
bogomips : 4390.03
clflush size : 64
cache_alignment : 64
address sizes : 45 bits physical, 48 bits virtual
power management:
[root@nerd-cafe ~]#2.2 View Memory Info
[root@nerd-cafe ~]# cat /proc/meminfo
MemTotal: 995460 kB
MemFree: 424448 kB
MemAvailable: 432864 kB
Buffers: 2108 kB
Cached: 149548 kB
SwapCached: 0 kB
Active: 311924 kB
Inactive: 129364 kB
Active(anon): 290100 kB
Inactive(anon): 25256 kB
Active(file): 21824 kB
Inactive(file): 104108 kB
Unevictable: 0 kB
Mlocked: 0 kB
SwapTotal: 839676 kB
SwapFree: 839676 kB
Dirty: 8 kB
Writeback: 0 kB
AnonPages: 289664 kB
Mapped: 58644 kB
Shmem: 25724 kB
Slab: 57496 kB
SReclaimable: 20364 kB
SUnreclaim: 37132 kB
KernelStack: 4048 kB
PageTables: 9304 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
WritebackTmp: 0 kB
CommitLimit: 1337404 kB
Committed_AS: 968220 kB
VmallocTotal: 34359738367 kB
VmallocUsed: 180460 kB
VmallocChunk: 34359310332 kB
Percpu: 33280 kB
HardwareCorrupted: 0 kB
AnonHugePages: 206848 kB
CmaTotal: 0 kB
CmaFree: 0 kB
HugePages_Total: 0
HugePages_Free: 0
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 2048 kB
DirectMap4k: 73600 kB
DirectMap2M: 974848 kB
[root@nerd-cafe ~]#2.3 Check Disk Drives
[root@nerd-cafe ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 8G 0 disk
├─sda1 8:1 0 1G 0 part /boot
└─sda2 8:2 0 7G 0 part
├─centos-root 253:0 0 6.2G 0 lvm /
└─centos-swap 253:1 0 820M 0 lvm [SWAP]
sr0 11:0 1 1024M 0 rom
[root@nerd-cafe ~]#or use:
[root@nerd-cafe ~]# fdisk -l
Disk /dev/sda: 8589 MB, 8589934592 bytes, 16777216 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x000ec008
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 2099199 1048576 83 Linux
/dev/sda2 2099200 16777215 7339008 8e Linux LVM
Disk /dev/mapper/centos-root: 6652 MB, 6652166144 bytes, 12992512 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mapper/centos-swap: 859 MB, 859832320 bytes, 1679360 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
[root@nerd-cafe ~]#2.4 View PCI Devices (e.g. network cards, GPUs)
[root@nerd-cafe ~]# lspci
00:00.0 Host bridge: Intel Corporation 440BX/ZX/DX - 82443BX/ZX/DX Host bridge (rev 01)
00:01.0 PCI bridge: Intel Corporation 440BX/ZX/DX - 82443BX/ZX/DX AGP bridge (rev 01)
00:07.0 ISA bridge: Intel Corporation 82371AB/EB/MB PIIX4 ISA (rev 08)
00:07.1 IDE interface: Intel Corporation 82371AB/EB/MB PIIX4 IDE (rev 01)
00:07.3 Bridge: Intel Corporation 82371AB/EB/MB PIIX4 ACPI (rev 08)
00:07.7 System peripheral: VMware Virtual Machine Communication Interface (rev 10)
00:0f.0 VGA compatible controller: VMware SVGA II Adapter
00:10.0 SCSI storage controller: Broadcom / LSI 53c1030 PCI-X Fusion-MPT Dual Ultra320 SCSI (rev 01)
00:11.0 PCI bridge: VMware PCI bridge (rev 02)
00:15.0 PCI bridge: VMware PCI Express Root Port (rev 01)
00:15.1 PCI bridge: VMware PCI Express Root Port (rev 01)
00:15.2 PCI bridge: VMware PCI Express Root Port (rev 01)
00:15.3 PCI bridge: VMware PCI Express Root Port (rev 01)
00:15.4 PCI bridge: VMware PCI Express Root Port (rev 01)
00:15.5 PCI bridge: VMware PCI Express Root Port (rev 01)
00:15.6 PCI bridge: VMware PCI Express Root Port (rev 01)
00:15.7 PCI bridge: VMware PCI Express Root Port (rev 01)
00:16.0 PCI bridge: VMware PCI Express Root Port (rev 01)
00:16.1 PCI bridge: VMware PCI Express Root Port (rev 01)
00:16.2 PCI bridge: VMware PCI Express Root Port (rev 01)
00:16.3 PCI bridge: VMware PCI Express Root Port (rev 01)
00:16.4 PCI bridge: VMware PCI Express Root Port (rev 01)
00:16.5 PCI bridge: VMware PCI Express Root Port (rev 01)
00:16.6 PCI bridge: VMware PCI Express Root Port (rev 01)
00:16.7 PCI bridge: VMware PCI Express Root Port (rev 01)
00:17.0 PCI bridge: VMware PCI Express Root Port (rev 01)
00:17.1 PCI bridge: VMware PCI Express Root Port (rev 01)
00:17.2 PCI bridge: VMware PCI Express Root Port (rev 01)
00:17.3 PCI bridge: VMware PCI Express Root Port (rev 01)
00:17.4 PCI bridge: VMware PCI Express Root Port (rev 01)
00:17.5 PCI bridge: VMware PCI Express Root Port (rev 01)
00:17.6 PCI bridge: VMware PCI Express Root Port (rev 01)
00:17.7 PCI bridge: VMware PCI Express Root Port (rev 01)
00:18.0 PCI bridge: VMware PCI Express Root Port (rev 01)
00:18.1 PCI bridge: VMware PCI Express Root Port (rev 01)
00:18.2 PCI bridge: VMware PCI Express Root Port (rev 01)
00:18.3 PCI bridge: VMware PCI Express Root Port (rev 01)
00:18.4 PCI bridge: VMware PCI Express Root Port (rev 01)
00:18.5 PCI bridge: VMware PCI Express Root Port (rev 01)
00:18.6 PCI bridge: VMware PCI Express Root Port (rev 01)
00:18.7 PCI bridge: VMware PCI Express Root Port (rev 01)
02:00.0 USB controller: VMware USB1.1 UHCI Controller
02:01.0 Ethernet controller: Intel Corporation 82545EM Gigabit Ethernet Controller (Copper) (rev 01)
02:02.0 Ethernet controller: Intel Corporation 82545EM Gigabit Ethernet Controller (Copper) (rev 01)
02:04.0 USB controller: VMware USB2 EHCI Controller
[root@nerd-cafe ~]#You can install pciutils if lspci is not found:
[root@nerd-cafe ~]# sudo yum install pciutils2.5 View USB Devices
[root@nerd-cafe ~]# lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 003: ID 0e0f:0002 VMware, Inc. Virtual USB Hub
Bus 002 Device 002: ID 0e0f:0003 VMware, Inc. Virtual Mouse
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
[root@nerd-cafe ~]#Install usbutils if needed:
[root@nerd-cafe ~]# sudo yum install usbutilsStep 3: Kernel Messages and dmesg
3.1 View Boot Hardware Messages
[root@nerd-cafe ~]# dmesg | lessUseful filters:
[root@nerd-cafe ~]# dmesg | grep -i usb
[ 0.442446] ACPI: bus type USB registered
[ 0.442463] usbcore: registered new interface driver usbfs
[ 0.442471] usbcore: registered new interface driver hub
[ 0.442545] usbcore: registered new device driver usb
[ 0.885826] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
[ 0.886259] ehci-pci 0000:02:04.0: new USB bus registered, assigned bus number 1
[ 0.893015] ehci-pci 0000:02:04.0: USB 2.0 started, EHCI 1.00
[ 0.893120] usb usb1: New USB device found, idVendor=1d6b, idProduct=0002, bcdDevice= 3.10
[ 0.893122] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[ 0.893124] usb usb1: Product: EHCI Host Controller
[ 0.893126] usb usb1: Manufacturer: Linux 3.10.0-1160.102.1.el7.x86_64 ehci_hcd
[ 0.893128] usb usb1: SerialNumber: 0000:02:04.0
[ 0.893244] hub 1-0:1.0: USB hub found
[ 0.893469] ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver
[ 0.893497] uhci_hcd: USB Universal Host Controller Interface driver
[ 0.893936] uhci_hcd 0000:02:00.0: new USB bus registered, assigned bus number 2
[ 0.894385] usb usb2: New USB device found, idVendor=1d6b, idProduct=0001, bcdDevice= 3.10
[ 0.894387] usb usb2: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[ 0.894389] usb usb2: Product: UHCI Host Controller
[ 0.894391] usb usb2: Manufacturer: Linux 3.10.0-1160.102.1.el7.x86_64 uhci_hcd
[ 0.894392] usb usb2: SerialNumber: 0000:02:00.0
[ 0.894490] hub 2-0:1.0: USB hub found
[ 0.894742] usbcore: registered new interface driver usbserial_generic
[ 0.894749] usbserial: USB Serial support registered for generic
[ 0.901352] usbcore: registered new interface driver usbhid
[ 0.901353] usbhid: USB HID core driver
[ 1.205798] usb 2-1: new full-speed USB device number 2 using uhci_hcd
[ 1.345738] usb 2-1: New USB device found, idVendor=0e0f, idProduct=0003, bcdDevice= 1.03
[ 1.345743] usb 2-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[ 1.345746] usb 2-1: Product: VMware Virtual USB Mouse
[ 1.345748] usb 2-1: Manufacturer: VMware
[ 1.357301] input: VMware VMware Virtual USB Mouse as /devices/pci0000:00/0000:00:11.0/0000:02:00.0/usb2/2-1/2-1:1.0/input/input4
[ 1.357431] hid-generic 0003:0E0F:0003.0001: input,hidraw0: USB HID v1.10 Mouse [VMware VMware Virtual USB Mouse] on usb-0000:02:00.0-1/input0
[ 1.469771] usb 2-2: new full-speed USB device number 3 using uhci_hcd
[ 1.610598] usb 2-2: New USB device found, idVendor=0e0f, idProduct=0002, bcdDevice= 1.00
[ 1.610602] usb 2-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[ 1.610604] usb 2-2: Product: VMware Virtual USB Hub
[ 1.610606] usb 2-2: Manufacturer: VMware, Inc.
[ 1.618097] hub 2-2:1.0: USB hub found
[root@nerd-cafe ~]#or:
[root@nerd-cafe ~]# dmesg | grep -i eth
[ 2.556039] e1000 0000:02:01.0 eth0: (PCI:66MHz:32-bit) 00:0c:29:48:46:e1
[ 2.556047] e1000 0000:02:01.0 eth0: Intel(R) PRO/1000 Network Connection
[ 2.957370] e1000 0000:02:02.0 eth1: (PCI:66MHz:32-bit) 00:0c:29:48:46:eb
[ 2.957376] e1000 0000:02:02.0 eth1: Intel(R) PRO/1000 Network Connection
[root@nerd-cafe ~]#This shows how hardware was detected and initialized during boot.
Step 4: Kernel Modules (Drivers)
Linux uses kernel modules to load drivers dynamically.
4.1 List Loaded Kernel Modules
[root@nerd-cafe ~]# lsmod
Module Size Used by
ip6t_rpfilter 12595 1
ip6t_REJECT 12625 2
nf_reject_ipv6 13717 1 ip6t_REJECT
ipt_REJECT 12541 2
nf_reject_ipv4 13373 1 ipt_REJECT
xt_conntrack 12760 13
ebtable_nat 12807 1
ebtable_broute 12731 1
bridge 155432 1 ebtable_broute
stp 12976 1 bridge
llc 14552 2 stp,bridge
ip6table_nat 12864 1
nf_conntrack_ipv6 18935 8
nf_defrag_ipv6 35104 1 nf_conntrack_ipv6
nf_nat_ipv6 14131 1 ip6table_nat
ip6table_mangle 12700 1
ip6table_security 12710 1
ip6table_raw 12683 1
iptable_nat 12875 1
nf_conntrack_ipv4 19149 7
nf_defrag_ipv4 12729 1 nf_conntrack_ipv4
nf_nat_ipv4 14115 1 iptable_nat
nf_nat 26583 2 nf_nat_ipv4,nf_nat_ipv6
iptable_mangle 12695 1
iptable_security 12705 1
iptable_raw 12678 1
nf_conntrack 143411 6 nf_nat,nf_nat_ipv4,nf_nat_ipv6,xt_conntrack,nf_conntrack_ipv4,nf_conntrack_ipv6
ip_set 45799 0
ebtable_filter 12827 1
ebtables 35009 3 ebtable_broute,ebtable_nat,ebtable_filter
ip6table_filter 12815 1
ip6_tables 26912 5 ip6table_filter,ip6table_mangle,ip6table_security,ip6table_nat,ip6table_raw
iptable_filter 12810 1
iosf_mbi 15582 0
crc32_pclmul 13133 0
ppdev 17671 0
ghash_clmulni_intel 13273 0
aesni_intel 189456 0
lrw 13286 1 aesni_intel
gf128mul 15139 1 lrw
glue_helper 13990 1 aesni_intel
ablk_helper 13597 1 aesni_intel
cryptd 21190 3 ghash_clmulni_intel,aesni_intel,ablk_helper
vmw_balloon 18094 0
pcspkr 12718 0
joydev 17389 0
sg 40719 0
vmw_vmci 67168 0
i2c_piix4 22401 0
parport_pc 28205 0
parport 46395 2 ppdev,parport_pc
ip_tables 27126 5 iptable_security,iptable_filter,iptable_mangle,iptable_nat,iptable_raw
xfs 1014152 2
libcrc32c 12644 3 xfs,nf_nat,nf_conntrack
sr_mod 22416 0
cdrom 46696 1 sr_mod
ata_generic 12923 0
pata_acpi 13053 0
vmwgfx 296089 1
sd_mod 46281 3
crc_t10dif 12912 1 sd_mod
drm_kms_helper 186531 1 vmwgfx
crct10dif_generic 12647 0
syscopyarea 12529 1 drm_kms_helper
sysfillrect 12701 1 drm_kms_helper
sysimgblt 12640 1 drm_kms_helper
fb_sys_fops 12703 1 drm_kms_helper
ttm 100769 1 vmwgfx
crct10dif_pclmul 14307 1
crct10dif_common 12595 3 crct10dif_pclmul,crct10dif_generic,crc_t10dif
crc32c_intel 22094 1
drm 468454 4 ttm,drm_kms_helper,vmwgfx
ata_piix 35052 0
nfit 59735 0
mptspi 22673 2
serio_raw 13434 0
libata 247190 3 pata_acpi,ata_generic,ata_piix
scsi_transport_spi 30732 1 mptspi
libnvdimm 163620 1 nfit
e1000 137624 0
mptscsih 40150 1 mptspi
mptbase 106036 2 mptspi,mptscsih
drm_panel_orientation_quirks 17180 1 drm
dm_mirror 22326 0
dm_region_hash 20813 1 dm_mirror
dm_log 18411 2 dm_region_hash,dm_mirror
dm_mod 128595 8 dm_log,dm_mirror
[root@nerd-cafe ~]#4.2 Load a Kernel Module
[root@nerd-cafe ~]# sudo modprobe <module_name>Example: To load the e1000e network driver:
[root@nerd-cafe ~]# sudo modprobe e1000e4.3 Unload a Kernel Module
[root@nerd-cafe ~]# sudo modprobe -r <module_name>4.4 Check Module Info
[root@nerd-cafe ~]# modinfo e1000e
filename: /lib/modules/3.10.0-1160.102.1.el7.x86_64/kernel/drivers/net/ethernet/intel/e1000e/e1000e.ko.xz
version: 3.2.6-k
license: GPL v2
description: Intel(R) PRO/1000 Network Driver
author: Intel Corporation, <[email protected]>
retpoline: Y
rhelversion: 7.9
srcversion: 098ECE9B1EBA1A3C30EA7ED
alias: pci:v00008086d000015E2sv*sd*bc*sc*i*
...
alias: pci:v00008086d0000105Esv*sd*bc*sc*i*
depends: ptp
intree: Y
vermagic: 3.10.0-1160.102.1.el7.x86_64 SMP mod_unload modversions
signer: CentOS Linux kernel signing key
sig_key: 56:7C:0A:85:06:C7:C3:00:F0:66:03:5C:EA:63:E5:BA:FD:E2:3F:DA
sig_hashalgo: sha256
parm: debug:Debug level (0=none,...,16=all) (int)
parm: copybreak:Maximum size of packet that is copied to a new buffer on receive (uint)
parm: TxIntDelay:Transmit Interrupt Delay (array of int)
parm: TxAbsIntDelay:Transmit Absolute Interrupt Delay (array of int)
parm: RxIntDelay:Receive Interrupt Delay (array of int)
parm: RxAbsIntDelay:Receive Absolute Interrupt Delay (array of int)
parm: InterruptThrottleRate:Interrupt Throttling Rate (array of int)
parm: IntMode:Interrupt Mode (array of int)
parm: SmartPowerDownEnable:Enable PHY smart power down (array of int)
parm: KumeranLockLoss:Enable Kumeran lock loss workaround (array of int)
parm: WriteProtectNVM:Write-protect NVM [WARNING: disabling this can lead to corrupted NVM] (array of int)
parm: CrcStripping:Enable CRC Stripping, disable if your BMC needs the CRC (array of int)
[root@nerd-cafe ~]#Step 5: Configure Modules to Load at Boot
Edit /etc/modules-load.d/ or use /etc/modprobe.d/
Example: Auto-load loop module on boot
loop module on boot[root@nerd-cafe ~]# echo loop | sudo tee /etc/modules-load.d/loop.conf
loop
[root@nerd-cafe ~]#Step 6: Check and Configure IRQs and DMA (optional for most modern systems)
View interrupt requests (IRQs):
[root@nerd-cafe ~]# cat /proc/interrupts
CPU0
0: 112 IO-APIC-edge timer
1: 42 IO-APIC-edge i8042
8: 1 IO-APIC-edge rtc0
9: 0 IO-APIC-fasteoi acpi
12: 127 IO-APIC-edge i8042
14: 0 IO-APIC-edge ata_piix
15: 3131 IO-APIC-edge ata_piix
16: 4715 IO-APIC-fasteoi vmwgfx, ens34
17: 11450 IO-APIC-fasteoi ioc0
18: 65 IO-APIC-fasteoi ehci_hcd:usb1, uhci_hcd:usb2
19: 25454 IO-APIC-fasteoi ens33
24: 0 PCI-MSI-edge PCIe PME, pciehp
25: 0 PCI-MSI-edge PCIe PME, pciehp
26: 0 PCI-MSI-edge PCIe PME, pciehp
27: 0 PCI-MSI-edge PCIe PME, pciehp
28: 0 PCI-MSI-edge PCIe PME, pciehp
29: 0 PCI-MSI-edge PCIe PME, pciehp
30: 0 PCI-MSI-edge PCIe PME, pciehp
31: 0 PCI-MSI-edge PCIe PME, pciehp
32: 0 PCI-MSI-edge PCIe PME, pciehp
33: 0 PCI-MSI-edge PCIe PME, pciehp
34: 0 PCI-MSI-edge PCIe PME, pciehp
35: 0 PCI-MSI-edge PCIe PME, pciehp
36: 0 PCI-MSI-edge PCIe PME, pciehp
37: 0 PCI-MSI-edge PCIe PME, pciehp
38: 0 PCI-MSI-edge PCIe PME, pciehp
39: 0 PCI-MSI-edge PCIe PME, pciehp
40: 0 PCI-MSI-edge PCIe PME, pciehp
41: 0 PCI-MSI-edge PCIe PME, pciehp
42: 0 PCI-MSI-edge PCIe PME, pciehp
43: 0 PCI-MSI-edge PCIe PME, pciehp
44: 0 PCI-MSI-edge PCIe PME, pciehp
45: 0 PCI-MSI-edge PCIe PME, pciehp
46: 0 PCI-MSI-edge PCIe PME, pciehp
47: 0 PCI-MSI-edge PCIe PME, pciehp
48: 0 PCI-MSI-edge PCIe PME, pciehp
49: 0 PCI-MSI-edge PCIe PME, pciehp
50: 0 PCI-MSI-edge PCIe PME, pciehp
51: 0 PCI-MSI-edge PCIe PME, pciehp
52: 0 PCI-MSI-edge PCIe PME, pciehp
53: 0 PCI-MSI-edge PCIe PME, pciehp
54: 0 PCI-MSI-edge PCIe PME, pciehp
55: 0 PCI-MSI-edge PCIe PME, pciehp
56: 0 PCI-MSI-edge vmw_vmci
57: 0 PCI-MSI-edge vmw_vmci
NMI: 0 Non-maskable interrupts
LOC: 132836 Local timer interrupts
SPU: 0 Spurious interrupts
PMI: 0 Performance monitoring interrupts
IWI: 7203 IRQ work interrupts
RTR: 0 APIC ICR read retries
RES: 0 Rescheduling interrupts
CAL: 0 Function call interrupts
TLB: 0 TLB shootdowns
TRM: 0 Thermal event interrupts
THR: 0 Threshold APIC interrupts
DFR: 0 Deferred Error APIC interrupts
MCE: 0 Machine check exceptions
MCP: 12 Machine check polls
ERR: 0
MIS: 0
PIN: 0 Posted-interrupt notification event
NPI: 0 Nested posted-interrupt event
PIW: 0 Posted-interrupt wakeup event
[root@nerd-cafe ~]#Direct memory access (DMA) channels (less relevant on modern systems):
[root@nerd-cafe ~]# cat /proc/dma
4: cascade
[root@nerd-cafe ~]#Step 7: Troubleshoot Hardware Detection
Check
dmesgfor errors.Use
lspci -vorlsusb -vfor detailed info.If a device is not working, identify its driver and ensure the module is loaded.
Check logs:
[root@nerd-cafe ~]# sudo journalctl -kSummary of Important Commands
Command
Description
cat /proc/cpuinfo
View CPU details
cat /proc/meminfo
View memory usage
lsblk
List block storage devices
lspci
List PCI devices
lsusb
List USB devices
dmesg
Kernel and boot messages
lsmod
Show loaded modules
modprobe
Load/unload kernel modules
modinfo
View module info
journalctl -k
Kernel log messages
Keywords
BIOS, UEFI, CPU info, memory info, lsblk, fdisk, lspci, lsusb, dmesg, kernel modules, lsmod, modprobe, modinfo, CentOS, IRQ, DMA, journalctl, hardware detection, boot process, hardware configuration, nerd cafe
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