Stderr output

<core_client_version>8.0.2</core_client_version>
<![CDATA[
<message>
Unspecified error
 (0x80004005) - exit code 2147500037 (0x80004005)</message>
<stderr_txt>
2026-02-27 13:35:05 (68652): vboxwrapper version 26210
2026-02-27 13:35:05 (68652): BOINC client version: 8.0.2
2026-02-27 13:35:06 (68652): Detected: VirtualBox VboxManage Interface (Version: 7.2.6)
2026-02-27 13:35:06 (68652): Detected: Heartbeat check (file: 'heartbeat' every 1200.000000 seconds)
2026-02-27 13:35:06 (68652): Successfully copied 'init_data.xml' to the shared directory.
2026-02-27 13:35:06 (68652): Create VM. (boinc_fcb19d24959a7cc5, slot#2)
2026-02-27 13:35:07 (68652): Setting Memory Size for VM. (4584MB)
2026-02-27 13:35:07 (68652): Setting CPU Count for VM. (4)
2026-02-27 13:35:07 (68652): Setting Chipset Options for VM.
2026-02-27 13:35:08 (68652): Setting Graphics Controller Options for VM. (Driver: VBoxVGA, 16MB)
2026-02-27 13:35:08 (68652): Setting Boot Options for VM.
2026-02-27 13:35:09 (68652): Setting Network Configuration for NAT. (Driver: virtio)
2026-02-27 13:35:09 (68652): Enabling VM Network Access.
2026-02-27 13:35:09 (68652): Disabling USB Support for VM.
2026-02-27 13:35:09 (68652): Disabling COM Port Support for VM.
2026-02-27 13:35:10 (68652): Disabling LPT Port Support for VM.
2026-02-27 13:35:10 (68652): Disabling Audio Support for VM.
2026-02-27 13:35:10 (68652): Disabling Clipboard Support for VM.
2026-02-27 13:35:10 (68652): Disabling Drag and Drop Support for VM.
2026-02-27 13:35:11 (68652): Adding storage controller(s) to VM.
2026-02-27 13:35:11 (68652): Adding virtual disk drive to VM. (CMS_2025_04_08_prod.vdi)
2026-02-27 13:35:13 (68652): Adding VirtualBox Guest Additions to VM.
2026-02-27 13:35:14 (68652): Adding network bandwidth throttle group to VM. (Defaulting to 1024GB)
2026-02-27 13:35:14 (68652): forwarding host port 55743 to guest port 80
2026-02-27 13:35:14 (68652): Enabling remote desktop for VM.
2026-02-27 13:35:14 (68652): Required extension pack not installed, remote desktop not enabled.
2026-02-27 13:35:14 (68652): Enabling shared directory for VM.
2026-02-27 13:35:15 (68652): Starting VM using VBoxManage interface. (boinc_fcb19d24959a7cc5, slot#2)
2026-02-27 13:35:21 (68652): Error in start VM for VM: -2147467259
Command:
VBoxManage -q startvm "boinc_fcb19d24959a7cc5" --type headless
Output:
VBoxManage.exe: error: Not in a hypervisor partition (HVP=0) (VERR_NEM_NOT_AVAILABLE).
VBoxManage.exe: error: VT-x is disabled in the BIOS for all CPU modes (VERR_VMX_MSR_ALL_VMX_DISABLED)
VBoxManage.exe: error: Details: code E_FAIL (0x80004005), component ConsoleWrap, interface IConsole
Waiting for VM "boinc_fcb19d24959a7cc5" to power on...

2026-02-27 13:35:21 (68652): VM failed to start.
2026-02-27 13:35:21 (68652): Could not start 
2026-02-27 13:35:21 (68652): ERROR: VM failed to start
2026-02-27 13:35:21 (68652): Powering off VM.
2026-02-27 13:35:21 (68652): Deregistering VM. (boinc_fcb19d24959a7cc5, slot#2)
2026-02-27 13:35:21 (68652): Removing network bandwidth throttle group from VM.
2026-02-27 13:35:21 (68652): Removing VM from VirtualBox.

    Hypervisor System Log:

00:00:07.223895          ERROR [COM]: aRC=VBOX_E_OBJECT_NOT_FOUND (0x80bb0001) aIID={e36a5081-a82a-40bd-9e4e-42a44d6ce50f} aComponent={SessionMachine} aText={No storage device attached to device slot 0 on port 0 of controller 'Hard Disk Controller'}, preserve=false aResultDetail=0
00:00:07.224160          Saving settings file "C:\Users\eduga\.VirtualBox\VirtualBox.xml" with version "1.12-windows"
00:00:07.232273          Finished saving settings file "C:\Users\eduga\.VirtualBox\VirtualBox.xml"
00:00:07.232896          Saving settings file "C:\ProgramData\BOINC\slots\2\boinc_fcb19d24959a7cc5\boinc_fcb19d24959a7cc5.vbox" with version "1.19-windows"
00:00:07.235697          Finished saving settings file "C:\ProgramData\BOINC\slots\2\boinc_fcb19d24959a7cc5\boinc_fcb19d24959a7cc5.vbox"
00:00:07.502594          Platform architecture set to 'x86'
00:00:07.505052          Saving settings file "C:\ProgramData\BOINC\slots\2\boinc_fcb19d24959a7cc5\boinc_fcb19d24959a7cc5.vbox" with version "1.19-windows"
00:00:07.512701          Finished saving settings file "C:\ProgramData\BOINC\slots\2\boinc_fcb19d24959a7cc5\boinc_fcb19d24959a7cc5.vbox"
00:00:07.767861          Platform architecture set to 'x86'
00:00:07.769875          ERROR [COM]: aRC=VBOX_E_OBJECT_NOT_FOUND (0x80bb0001) aIID={e36a5081-a82a-40bd-9e4e-42a44d6ce50f} aComponent={SessionMachine} aText={No storage device attached to device slot 0 on port 0 of controller 'Hard Disk Controller'}, preserve=false aResultDetail=0
00:00:07.770576          Saving settings file "C:\ProgramData\BOINC\slots\2\boinc_fcb19d24959a7cc5\boinc_fcb19d24959a7cc5.vbox" with version "1.19-windows"
00:00:07.778541          Finished saving settings file "C:\ProgramData\BOINC\slots\2\boinc_fcb19d24959a7cc5\boinc_fcb19d24959a7cc5.vbox"
00:00:07.778737          ERROR [COM]: aRC=VBOX_E_OBJECT_NOT_FOUND (0x80bb0001) aIID={e36a5081-a82a-40bd-9e4e-42a44d6ce50f} aComponent={SessionMachine} aText={No storage device attached to device slot 0 on port 0 of controller 'Hard Disk Controller'}, preserve=false aResultDetail=0
00:00:07.780621          Saving settings file "C:\ProgramData\BOINC\slots\2\boinc_fcb19d24959a7cc5\boinc_fcb19d24959a7cc5.vbox" with version "1.19-windows"
00:00:07.783279          Finished saving settings file "C:\ProgramData\BOINC\slots\2\boinc_fcb19d24959a7cc5\boinc_fcb19d24959a7cc5.vbox"
00:00:07.783944          Saving settings file "C:\ProgramData\BOINC\slots\2\boinc_fcb19d24959a7cc5\boinc_fcb19d24959a7cc5.vbox" with version "1.19-windows"
00:00:07.786525          Finished saving settings file "C:\ProgramData\BOINC\slots\2\boinc_fcb19d24959a7cc5\boinc_fcb19d24959a7cc5.vbox"
00:00:08.049428          Platform architecture set to 'x86'
00:00:08.051488          ERROR [COM]: aRC=VBOX_E_OBJECT_NOT_FOUND (0x80bb0001) aIID={e36a5081-a82a-40bd-9e4e-42a44d6ce50f} aComponent={SessionMachine} aText={No storage device attached to device slot 0 on port 1 of controller 'Hard Disk Controller'}, preserve=false aResultDetail=0
00:00:08.053275          ERROR [COM]: aRC=VBOX_E_OBJECT_NOT_FOUND (0x80bb0001) aIID={e36a5081-a82a-40bd-9e4e-42a44d6ce50f} aComponent={SessionMachine} aText={No storage device attached to device slot 0 on port 1 of controller 'Hard Disk Controller'}, preserve=false aResultDetail=0
00:00:08.053516          Saving settings file "C:\Users\eduga\.VirtualBox\VirtualBox.xml" with version "1.12-windows"
00:00:08.057321          Finished saving settings file "C:\Users\eduga\.VirtualBox\VirtualBox.xml"
00:00:08.057683          Saving settings file "C:\Users\eduga\.VirtualBox\VirtualBox.xml" with version "1.12-windows"
00:00:08.060478          Finished saving settings file "C:\Users\eduga\.VirtualBox\VirtualBox.xml"
00:00:08.060966          Saving settings file "C:\ProgramData\BOINC\slots\2\boinc_fcb19d24959a7cc5\boinc_fcb19d24959a7cc5.vbox" with version "1.19-windows"
00:00:08.063648          Finished saving settings file "C:\ProgramData\BOINC\slots\2\boinc_fcb19d24959a7cc5\boinc_fcb19d24959a7cc5.vbox"
00:00:08.331656          Platform architecture set to 'x86'
00:00:08.333441          Saving settings file "C:\ProgramData\BOINC\slots\2\boinc_fcb19d24959a7cc5\boinc_fcb19d24959a7cc5.vbox" with version "1.19-windows"
00:00:08.341801          Finished saving settings file "C:\ProgramData\BOINC\slots\2\boinc_fcb19d24959a7cc5\boinc_fcb19d24959a7cc5.vbox"
00:00:08.613066          Platform architecture set to 'x86'
00:00:08.615595          Saving settings file "C:\ProgramData\BOINC\slots\2\boinc_fcb19d24959a7cc5\boinc_fcb19d24959a7cc5.vbox" with version "1.19-windows"
00:00:08.623270          Finished saving settings file "C:\ProgramData\BOINC\slots\2\boinc_fcb19d24959a7cc5\boinc_fcb19d24959a7cc5.vbox"
00:00:09.159476          Platform architecture set to 'x86'
00:00:09.161099          Saving settings file "C:\ProgramData\BOINC\slots\2\boinc_fcb19d24959a7cc5\boinc_fcb19d24959a7cc5.vbox" with version "1.19-windows"
00:00:09.168883          Finished saving settings file "C:\ProgramData\BOINC\slots\2\boinc_fcb19d24959a7cc5\boinc_fcb19d24959a7cc5.vbox"
00:00:09.421425          Platform architecture set to 'x86'
00:00:09.423424          ERROR [COM]: aRC=VBOX_E_NOT_SUPPORTED (0x80bb0009) aIID={e36a5081-a82a-40bd-9e4e-42a44d6ce50f} aComponent={SessionMachine} aText={This VM is not encrypted}, preserve=false aResultDetail=0
00:00:09.429801          ERROR [COM]: aRC=VBOX_E_OBJECT_NOT_FOUND (0x80bb0001) aIID={e36a5081-a82a-40bd-9e4e-42a44d6ce50f} aComponent={SessionMachine} aText={No storage device attached to device slot 0 on port 2 of controller 'Hard Disk Controller'}, preserve=false aResultDetail=0
00:00:09.429883          ERROR [COM]: aRC=VBOX_E_OBJECT_NOT_FOUND (0x80bb0001) aIID={e36a5081-a82a-40bd-9e4e-42a44d6ce50f} aComponent={SessionMachine} aText={No storage device attached to device slot 0 on port 2 of controller 'Hard Disk Controller'}, preserve=false aResultDetail=0
00:00:09.437474          ERROR [COM]: aRC=E_FAIL (0x80004005) aIID={83cfdc66-4f20-4569-ad39-8722f7d472b3} aComponent={RecordingSettingsWrap} aText={Recording not started}, preserve=false aResultDetail=0
00:00:09.438408          ERROR [COM]: aRC=E_FAIL (0x80004005) aIID={e36a5081-a82a-40bd-9e4e-42a44d6ce50f} aComponent={SessionMachine} aText={This machine does not have any snapshots}, preserve=false aResultDetail=0
00:00:09.720880          Launched VM: 3086466784 pid: 69588 (0x10fd4) frontend: headless name: boinc_fcb19d24959a7cc5
00:00:14.437737          Platform architecture set to 'x86'
00:00:15.521397          Saving settings file "C:\ProgramData\BOINC\slots\2\boinc_fcb19d24959a7cc5\boinc_fcb19d24959a7cc5.vbox" with version "1.19-windows"
00:00:15.525060          Finished saving settings file "C:\ProgramData\BOINC\slots\2\boinc_fcb19d24959a7cc5\boinc_fcb19d24959a7cc5.vbox"
00:00:15.633518          ERROR [COM]: aRC=E_FAIL (0x80004005) aIID={e36a5081-a82a-40bd-9e4e-42a44d6ce50f} aComponent={SessionMachine} aText={This machine does not have any snapshots}, preserve=false aResultDetail=0
00:00:16.013871          Saving settings file "C:\Users\eduga\.VirtualBox\VirtualBox.xml" with version "1.12-windows"
00:00:16.017593          Finished saving settings file "C:\Users\eduga\.VirtualBox\VirtualBox.xml"
00:00:16.017889          Saving settings file "C:\Users\eduga\.VirtualBox\VirtualBox.xml" with version "1.12-windows"
00:00:16.021220          Finished saving settings file "C:\Users\eduga\.VirtualBox\VirtualBox.xml"
00:00:16.022336 DeleteVM Saving settings file "C:\Users\eduga\.VirtualBox\VirtualBox.xml" with version "1.12-windows"
00:00:16.025557 DeleteVM Finished saving settings file "C:\Users\eduga\.VirtualBox\VirtualBox.xml"
00:00:21.041920 main     VirtualBox: object deletion starts
00:00:21.044593 main     HostDnsMonitor: shutting down ...
00:00:21.044624 main     HostDnsMonitor: shut down
00:00:21.046287 Watcher  ERROR [COM]: aRC=E_ACCESSDENIED (0x80070005) aIID={2ce10519-3c09-45d8-a12d-e887786146b7} aComponent={VirtualBoxWrap} aText={The object is not ready}, preserve=false aResultDetail=0
00:00:21.046846 main     VirtualBox: object deleted

    VM Execution Log:


    VM Startup Log:


    VM Trace Log:

ing-config=""
autostart-enabled="off"
autostart-delay=0
defaultfrontend=""
vmprocpriority="default"
natnet1="nat"
macaddress1="0800278386BB"
cableconnected1="on"
nic1="nat"
nictype1="82540EM"
nicspeed1="0"
mtu="0"
sockSnd="64"
sockRcv="64"
tcpWndSnd="64"
tcpWndRcv="64"
localhostReachable="0"
forwardBroadcast="0"
enableTFTP="0"
nic2="none"
nic3="none"
nic4="none"
nic5="none"
nic6="none"
nic7="none"
nic8="none"
hidpointing="ps2mouse"
hidkeyboard="ps2kbd"
uart1="off"
uart2="off"
uart3="off"
uart4="off"
lpt1="off"
lpt2="off"
audio="default"
audio_out="off"
audio_in="off"
clipboard="disabled"
clipboard_file_transfers="off"
draganddrop="disabled"
vrde="off"
usb="off"
ehci="off"
xhci="off"
recording_started="off"
recording_enabled="off"
recording_screens=1
 rec_screen0
rec_screen_enabled="on"
rec_screen_id=0
rec_screen_video_enabled="on"
rec_screen_audio_enabled="off"
rec_screen_dest="File"
rec_screen_dest_filename="C:\\ProgramData\\BOINC\\slots\\2\\boinc_fcb19d24959a7cc5\\boinc_fcb19d24959a7cc5-screen0.webm"
rec_screen_opts="ac_profile=med"
rec_screen_video_res_xy="1024x768"
rec_screen_video_rate_kbps=512
rec_screen_video_fps=25
description="CMS_798180_1772206865.796641_0"
GuestMemoryBalloon=0

2026-02-27 13:35:09 (68652): 
Command: VBoxManage -q modifyvm "boinc_fcb19d24959a7cc5" --nic1 nat --nic-type1 "virtio" --cable-connected1 off --nat-dns-proxy1 on 
Exit Code: 0
Output:

2026-02-27 13:35:09 (68652): 
Command: VBoxManage -q modifyvm "boinc_fcb19d24959a7cc5" --cable-connected1 on 
Exit Code: 0
Output:

2026-02-27 13:35:09 (68652): 
Command: VBoxManage -q modifyvm "boinc_fcb19d24959a7cc5" --usb off 
Exit Code: 0
Output:

2026-02-27 13:35:10 (68652): 
Command: VBoxManage -q modifyvm "boinc_fcb19d24959a7cc5" --uart1 off --uart2 off 
Exit Code: 0
Output:

2026-02-27 13:35:10 (68652): 
Command: VBoxManage -q modifyvm "boinc_fcb19d24959a7cc5" --lpt1 off --lpt2 off 
Exit Code: 0
Output:

2026-02-27 13:35:10 (68652): 
Command: VBoxManage -q modifyvm "boinc_fcb19d24959a7cc5" --audio-enabled off 
Exit Code: 0
Output:

2026-02-27 13:35:10 (68652): 
Command: VBoxManage -q modifyvm "boinc_fcb19d24959a7cc5" --clipboard disabled 
Exit Code: 0
Output:

2026-02-27 13:35:11 (68652): 
Command: VBoxManage -q modifyvm "boinc_fcb19d24959a7cc5" --draganddrop disabled 
Exit Code: 0
Output:

2026-02-27 13:35:11 (68652): 
Command: VBoxManage -q storagectl "boinc_fcb19d24959a7cc5" --name "Hard Disk Controller" --add "sata" --controller "IntelAHCI" --hostiocache off --portcount 3
Exit Code: 0
Output:

2026-02-27 13:35:11 (68652): 
Command: VBoxManage -q showhdinfo "C:\ProgramData\BOINC/projects/lhcathome.cern.ch_lhcathome/CMS_2025_04_08_prod.vdi" 
Exit Code: 0
Output:
UUID:           fa49c4e2-ad29-47a5-b96a-3c89ce80d84c
Parent UUID:    base
State:          created
Type:           multiattach
Location:       C:\ProgramData\BOINC\projects\lhcathome.cern.ch_lhcathome\CMS_2025_04_08_prod.vdi
Storage format: VDI
Format variant: dynamic default
Capacity:       20480 MBytes
Size on disk:   3853 MBytes
Encryption:     disabled
Property:       AllocationBlockSize=1048576

2026-02-27 13:35:12 (68652): 
Command: VBoxManage -q storageattach "boinc_fcb19d24959a7cc5" --storagectl "Hard Disk Controller" --port 0 --device 0 --type hdd --mtype multiattach --medium "C:\ProgramData\BOINC/projects/lhcathome.cern.ch_lhcathome/CMS_2025_04_08_prod.vdi" 
Exit Code: -2135228409
Output:
VBoxManage.exe: error: Cannot attach medium 'C:\ProgramData\BOINC\projects\lhcathome.cern.ch_lhcathome\CMS_2025_04_08_prod.vdi': the media type 'MultiAttach' can only be attached to machines that were created with VirtualBox 4.0 or later
VBoxManage.exe: error: Details: code VBOX_E_INVALID_OBJECT_STATE (0x80bb0007), component SessionMachine, interface IMachine, callee IUnknown
VBoxManage.exe: error: Context: "AttachDevice(Bstr(pszCtl).raw(), port, device, DeviceType_HardDisk, pMedium2Mount)" at line 786 of file VBoxManageStorageController.cpp

2026-02-27 13:35:12 (68652): 
Command: VBoxManage -q showhdinfo "C:\ProgramData\BOINC/projects/lhcathome.cern.ch_lhcathome/CMS_2025_04_08_prod.vdi" 
Exit Code: 0
Output:
UUID:           fa49c4e2-ad29-47a5-b96a-3c89ce80d84c
Parent UUID:    base
State:          created
Type:           multiattach
Location:       C:\ProgramData\BOINC\projects\lhcathome.cern.ch_lhcathome\CMS_2025_04_08_prod.vdi
Storage format: VDI
Format variant: dynamic default
Capacity:       20480 MBytes
Size on disk:   3853 MBytes
Encryption:     disabled
Property:       AllocationBlockSize=1048576

2026-02-27 13:35:12 (68652): 
Command: VBoxManage -q closemedium disk "C:\ProgramData\BOINC\projects\lhcathome.cern.ch_lhcathome\CMS_2025_04_08_prod.vdi" 
Exit Code: 0
Output:

2026-02-27 13:35:12 (68652): 
Command: VBoxManage -q showhdinfo "C:\ProgramData\BOINC/projects/lhcathome.cern.ch_lhcathome/CMS_2025_04_08_prod.vdi" 
Exit Code: 0
Output:
UUID:           fa49c4e2-ad29-47a5-b96a-3c89ce80d84c
Parent UUID:    base
State:          created
Type:           normal (base)
Location:       C:\ProgramData\BOINC\projects\lhcathome.cern.ch_lhcathome\CMS_2025_04_08_prod.vdi
Storage format: VDI
Format variant: dynamic default
Capacity:       20480 MBytes
Size on disk:   3853 MBytes
Encryption:     disabled
Property:       AllocationBlockSize=1048576

2026-02-27 13:35:13 (68652): 
Command: VBoxManage -q storageattach "boinc_fcb19d24959a7cc5" --storagectl "Hard Disk Controller" --port 0 --device 0 --type hdd --medium "C:\ProgramData\BOINC/projects/lhcathome.cern.ch_lhcathome/CMS_2025_04_08_prod.vdi" 
Exit Code: 0
Output:

2026-02-27 13:35:13 (68652): 
Command: VBoxManage -q storageattach "boinc_fcb19d24959a7cc5" --storagectl "Hard Disk Controller" --port 0 --device 0 --type hdd --medium none 
Exit Code: 0
Output:

2026-02-27 13:35:13 (68652): 
Command: VBoxManage -q storageattach "boinc_fcb19d24959a7cc5" --storagectl "Hard Disk Controller" --port 0 --device 0 --type hdd --mtype multiattach --medium "C:\ProgramData\BOINC/projects/lhcathome.cern.ch_lhcathome/CMS_2025_04_08_prod.vdi" 
Exit Code: 0
Output:

2026-02-27 13:35:14 (68652): 
Command: VBoxManage -q storageattach "boinc_fcb19d24959a7cc5" --storagectl "Hard Disk Controller" --port 1 --device 0 --type dvddrive --medium "C:\Program Files\Oracle\VirtualBox/VBoxGuestAdditions.iso" 
Exit Code: 0
Output:

2026-02-27 13:35:14 (68652): 
Command: VBoxManage -q bandwidthctl "boinc_fcb19d24959a7cc5" add "boinc_fcb19d24959a7cc5_net" --type network --limit 1024G 
Exit Code: 0
Output:

2026-02-27 13:35:14 (68652): 
Command: VBoxManage -q modifyvm "boinc_fcb19d24959a7cc5" --natpf1 ",tcp,127.0.0.1,55743,,80" 
Exit Code: 0
Output:

2026-02-27 13:35:14 (68652): 
Command: VBoxManage -q list extpacks
Exit Code: 0
Output:
Extension Packs: 0

2026-02-27 13:35:15 (68652): 
Command: VBoxManage -q sharedfolder add "boinc_fcb19d24959a7cc5" --name "shared" --hostpath "C:\ProgramData\BOINC\slots\2/shared"
Exit Code: 0
Output:

2026-02-27 13:35:21 (68652): 
Command: VBoxManage -q startvm "boinc_fcb19d24959a7cc5" --type headless
Exit Code: -2147467259
Output:
VBoxManage.exe: error: Not in a hypervisor partition (HVP=0) (VERR_NEM_NOT_AVAILABLE).
VBoxManage.exe: error: VT-x is disabled in the BIOS for all CPU modes (VERR_VMX_MSR_ALL_VMX_DISABLED)
VBoxManage.exe: error: Details: code E_FAIL (0x80004005), component ConsoleWrap, interface IConsole
Waiting for VM "boinc_fcb19d24959a7cc5" to power on...

2026-02-27 13:35:21 (68652): 
Command: VBoxManage -q snapshot "boinc_fcb19d24959a7cc5" list 
Exit Code: -108
Output:
This machine does not have any snapshots

2026-02-27 13:35:21 (68652): 
Command: VBoxManage -q bandwidthctl "boinc_fcb19d24959a7cc5" remove "boinc_fcb19d24959a7cc5_net" 
Exit Code: 0
Output:
VBoxManage.exe: error: Bandwidth groups cannot be deleted while the VM is running

2026-02-27 13:35:21 (68652): 
Command: VBoxManage -q unregistervm "boinc_fcb19d24959a7cc5" --delete 
Exit Code: 0
Output:
0%...10%...20%...30%...40%...50%...60%...70%...80%...90%...100%

2026-02-27 13:35:27 (68652): called boinc_finish(-2147467259)

</stderr_txt>
]]>

©2026 CERN