Montags and Clarisse's realtionship is weird. If she had not died I think they would have become a lot closer throughout the book. Clarisse seemed to bring out a different side of Montag. They way she would ask him questions and make things for him.
JKS stands for Java KeyStore. It is a repository of certificates (signed public keys) and [private] keys. You can export a certificate stored in a JKS file into a certificate file. You can use the keytool utility found in Java distributions to maintain your JKS trust and key repositories.
The disk file is essentially a complete and independent virtual machine. A disk file with the VMDK extension is a virtual machine using VMware virtualization products or other platforms that support VMDK files such as Sun XVM, QEMU, or VirtualBox. The VMDK file format competes with the Microsoft Virtual Hard Disk (VHD) format used with Virtual Server and Hyper-V hypervisors.