Single connection for multiple Get-WmiObject calls - powershell

Question

The script below successfully obtains the manufacturer, model, serial number, and operating system from each computer I provide in hostnames.txt. However, it is slow because it must connect to WMI on each computer three times.
$OS = Get-WmiObject Win32_OperatingSystem -ComputerName $Computer
$CS = Get-WmiObject Win32_ComputerSystem -ComputerName $Computer
$BIOS = Get-WmiObject Win32_Bios -ComputerName $Computer
Using PowerShell, how can I connect to the remote-computer's WMI once and execute the three queries using the same connection?
$Array = #() ## Create Array to hold the Data
$Computers = Get-Content -Path .\hostnames.txt
foreach ($Computer in $Computers)
{
$Result = "" | Select HostPS,Mfg,Model,Serial,OS
$Result.HostPS = $Computer
$ErrorActionPreference = "SilentlyContinue" ## Don't output errors for offline computers
$OS = Get-WmiObject Win32_OperatingSystem -ComputerName $Computer
$CS = Get-WmiObject Win32_ComputerSystem -ComputerName $Computer
$BIOS = Get-WmiObject Win32_Bios -ComputerName $Computer
$ErrorActionPreference = "Continue"
$Result.Mfg = $CS.Manufacturer
$Result.Model = $CS.Model
$Result.Serial = $BIOS.SerialNumber
$Result.OS = $OS.Caption
$Array += $Result ## Add the data to the array
}
$Array | Export-Csv file.csv -NoTypeInformation

Answer 1

You can use CIM (which has a session option), more on CIM vs WMI ("WMI is the Microsoft implementation of CIM for the Windows platform")
$CIMSession = New-CimSession -ComputerName $RemoteComputer
Get-CimInstance win32_OperatingSystem -CimSession $CIMSession -Property Caption
Get-CimInstance Win32_ComputerSystem -CimSession $CIMSession -Property Manufacturer,Model
Get-CimInstance Win32_Bios -CimSession $CIMSession -Property SerialNumber

Answer 2

for me, the usual way to do that is to use Invoke-Command to run a script block on each target system. if you tell it to ignore errors, it will run in parallel [on the target systems] and return your data from the responders. to get the non-responders, compare the input list with the results. [grin]
here's a demo of the idea ...
#requires -RunAsAdministrator
# fake reading in a list of computer names
# in real life, use Get-Content or (Get-ADComputer).Name
$ComputerList = #'
Localhost
BetterNotBeThere
127.0.0.1
10.0.0.1
::1
'#.Split("`n").Trim("`r")
$IC_ScriptBlock = {
$CIM_ComputerSystem = Get-CimInstance -ClassName CIM_ComputerSystem
$CIM_BIOSElement = Get-CimInstance -ClassName CIM_BIOSElement
$CIM_OperatingSystem = Get-CimInstance -ClassName CIM_OperatingSystem
$CIM_Processor = Get-CimInstance -ClassName CIM_Processor
$CIM_LogicalDisk = Get-CimInstance -ClassName CIM_LogicalDisk |
Where-Object {$_.Name -eq $CIM_OperatingSystem.SystemDrive}
[PSCustomObject]#{
LocalComputerName = $env:COMPUTERNAME
Manufacturer = $CIM_ComputerSystem.Manufacturer
Model = $CIM_ComputerSystem.Model
SerialNumber = $CIM_BIOSElement.SerialNumber
CPU = $CIM_Processor.Name
RAM_GB = '{0:N2}' -f ($CIM_ComputerSystem.TotalPhysicalMemory / 1GB)
SysDrive_Capacity_GB = '{0:N2}' -f ($CIM_LogicalDisk.Size / 1GB)
SysDrive_FreeSpace_GB ='{0:N2}' -f ($CIM_LogicalDisk.FreeSpace / 1GB)
SysDrive_FreeSpace_Pct = '{0:N0}' -f ($CIM_LogicalDisk.FreeSpace / $CIM_LogicalDisk.Size * 100)
OperatingSystem_Name = $CIM_OperatingSystem.Caption
OperatingSystem_Version = $CIM_OperatingSystem.Version
OperatingSystem_BuildNumber = $CIM_OperatingSystem.BuildNumber
OperatingSystem_ServicePack = $CIM_OperatingSystem.ServicePackMajorVersion
CurrentUser = $CIM_ComputerSystem.UserName
LastBootUpTime = $CIM_OperatingSystem.LastBootUpTime
UpTime_Days = '{0:N2}' -f ([datetime]::Now - $CIM_OperatingSystem.LastBootUpTime).Days
}
}
$IC_Params = #{
ComputerName = $ComputerList
ScriptBlock = $IC_ScriptBlock
ErrorAction = 'SilentlyContinue'
}
$RespondingSystems = Invoke-Command #IC_Params
$NOT_RespondingSystems = $ComputerList.Where({
# these two variants are needed to deal with an ipv6 localhost address
"[$_]" -notin $RespondingSystems.PSComputerName -and
$_ -notin $RespondingSystems.PSComputerName
})
$RespondingSystems
$NOT_RespondingSystems
one item from the $RespondingSystems list ...
LocalComputerName : [MySystemName]
Manufacturer : System manufacturer
Model : System Product Name
SerialNumber : System Serial Number
CPU : AMD Phenom(tm) II X4 945 Processor
RAM_GB : 8.00
SysDrive_Capacity_GB : 931.41
SysDrive_FreeSpace_GB : 735.15
SysDrive_FreeSpace_Pct : 79
OperatingSystem_Name : Microsoft Windows 7 Professional
OperatingSystem_Version : 6.1.7601
OperatingSystem_BuildNumber : 7601
OperatingSystem_ServicePack : 1
CurrentUser : [MySystemName]\[MyUserName]
LastBootUpTime : 2018-10-19 7:01:51 PM
UpTime_Days : 7.00
PSComputerName : [::1]
RunspaceId : e17c2741-ba8b-4fbb-b3db-9c7fd0d84f0d
the $NOT_RespondingSystems list ...
BetterNotBeThere
10.0.0.1