Break the challenge down into its elements. The givens are:
1) a blank, formatted HDD with a driver in the PB. It can receive, but not give.
2) serial (miniDIN- 8) ports x 2, AAUI port, microphone port. The PB has to be 'listening' to these ports, using software that it doesn't have, for LocalTalk or AppleTalk networking. You cannot read a System onto the HDD via microphone.
3) SCSI HDI-30 port. This needs that the HDD spin up and be mounted on the desktop of some other fully sensate Mac, or accessible by a System on an external drive (HDD or CD-ROM).
4) Floppy disk drive. Can be used if you have a System on a bootable floppy disk from which to install System software onto the blank drive.
Thus, if you now possess System 7.1 on floppies, install 7.1 from those floppies onto the HDD, and then boot the PB from the HDD, thereafter you can use the FDD to transfer a complete 7.5.3 to a single folder on the desktop, and install 7.5.3 from that folder. What 'other' is needed? You have a means—not previously mentioned—of getting a bootable System onto the HDD, from which you can upgrade to any other supported System. You should also consider buying some larger hammers for future setup work: external drives, software, et alia.
de
1) a blank, formatted HDD with a driver in the PB. It can receive, but not give.
2) serial (miniDIN- 8) ports x 2, AAUI port, microphone port. The PB has to be 'listening' to these ports, using software that it doesn't have, for LocalTalk or AppleTalk networking. You cannot read a System onto the HDD via microphone.
3) SCSI HDI-30 port. This needs that the HDD spin up and be mounted on the desktop of some other fully sensate Mac, or accessible by a System on an external drive (HDD or CD-ROM).
4) Floppy disk drive. Can be used if you have a System on a bootable floppy disk from which to install System software onto the blank drive.
Thus, if you now possess System 7.1 on floppies, install 7.1 from those floppies onto the HDD, and then boot the PB from the HDD, thereafter you can use the FDD to transfer a complete 7.5.3 to a single folder on the desktop, and install 7.5.3 from that folder. What 'other' is needed? You have a means—not previously mentioned—of getting a bootable System onto the HDD, from which you can upgrade to any other supported System. You should also consider buying some larger hammers for future setup work: external drives, software, et alia.
de